Will Buddhism last only 5,000 years after Buddha's Mahaparinirvana?

Well, the Teaching's number is actually quite optimistic compared to the number that world renowned physicist Stephen Hawking gave, which is around 1,000 years when earth becomes completely unhabitable. So, no, there's no weak point in the Dhamma. The responsibility is squarely on us humans. How we've continue to mess up the earth and every single aspect of its eco-system. It's true that more folks are learning more about the Dhamma nowadays but that doesn't mean anything. Due to the information age, the average 21st century Buddhist's Dhamma knowledge vastly exceeds even learned monks in the old days. One can recite the entire Tipitaka and yet if s/he's not able to observe the most basic precept (like the Five Precepts for lay people), then his vast knowledge would mean absolutely nothing.

According to the Digital Dictionary of Buddhism (enter username: guest), which covers mostly Chinese and Japanese Mahayana traditions, there are three periods of the dharma:

...true dharma 正法, the semblance dharma 像法, and the degenerate dharma 末法.

Pure Land Buddhism came to popularity nearly 1000 years ago because of the belief that the earth had already entered the period of "degenerate dharma"—essentially the end times of dharma. In the current, degenerated era, no one is able to achieve enlightenment on their own and can only do so with help—that is, the help of Amitabha (阿彌陀佛).

From the Pure Land perspective, we are already well into the third period and must first progress to the Pure Land of Amitabha, a sort of staging ground where cultivation may continue, before it is possible to aspire to the ultimate goal of achieving Nirvana.

Buddhism will last 5000 years. How it will disappear? What Buddha said is Buddhism is magga-phala. That mean nobody will achieve magga-phala at that time of 5000 year after Buddha Mahaparinirvana. That mean magga-phala will disappear first at that time of 5000 year after Buddha Mahaparinirvana because nobody practice to achieve it anymore out of lobha, dosa and moha. After magga-phala disappear, nobody will know how to achieve it because only those who achieve nibbana will be able to teach one to be like that. Then the Buddha Dhamma literature will disappear with no more proper guidance. But magga-phala is still present during this 5000 years and everybody can achieve it during this 5000 years upto the arahantship. Please do not have doubt on this.

There has, does, will come a time when the teachings of the Buddha has been pulled into households, his "disciples" worship household and there teacher have been taken on signs of householders. Householder will teach housholder, worldlings, worldlings, i.e. Vinaya has disappeared in this world. With it's disappearing the (re)-ligion disappears and only "corrupted" Dhamma and improper ways to forward and gain the teachings will last. So it's up to anyone's devotion, respect and modesty whether one might possible meet of what still continues to run out in this world, from this appearance of Buddha, Dhamma, Sangha in a particular world-period.

What ever one nourishes inwardly and outwardly will continue to stay in ones world. What ever one stops to nourish inwardly and outwardly will disappear. It's all a matter of Upanissaya (strong seeds, strong foundation, strong conditions) and it's paccaya (causes, giving into,...) toward what. Some pull things down to where they are caught, some try to liberate them toward what leads or has gone beyond. Some are givers, but most are merely thieves. It's the nature of thieves to become imprisoned and deprived and only to stop such would be a future escape.

Now think where your explaining are from: homeless or those living in ways and with signs of householders?

And think about how you gained teachings or how those conducted who possible gave you a conscious share.

(This is not given for trade, exchange, stacks and entertainment bond or binding to the world but for a tiny exit of refuge and escape)

I can't find where the 5,000 year figure comes from in Theravada but it is mentioned that because Ananda begged The Buddha to allow women into the order that the pure dhamma would only last 500 years instead of 1,000 years:

"But since, Ananda, women have now received that permission, the pure Dhamma, Ananda, will not now last so long, the good law will now stand fast for only five hundred years." (PTS vp en BD.5.356)

I speculate that this would mean the disappearance of achievement of arahantship and the six higher knowledges (abhijñā) rather than the written disappearance of the teaching since it refers to the true dhamma or pure dhamma.

500 years after the parinibbana is around the same time-period that Buddhism started spreading all around the world.

According to DN 14 there were 1,250 arahants in the world during the time-period when The Buddha was alive and teaching. After the parinibbana I would guess much less and then 500 years later there were probably very few arahants in the world or maybe none at all.

Many think that the written or oral recited teachings surviving indicates that the dhamma is strong but there are many instances when The Buddha refutes this idea such as this one:

"Thus, bhikkhus, do I declare that it is through the Dhamma that one becomes a brahmin possessing the threefold knowledge; (I do not say this) of another merely because he can talk persuasively and recite."

"He who knows his former lives, Who sees heaven and states of woe, Who reaches the end of birth, A sage and master of direct knowledge—"

"By these three ways of knowing one becomes A brahmin having the threefold knowledge. That is what I call the threefold knowledge, Not another’s babbling and reciting." (Tevijja Sutta, Iti 99)

Being able to debate, talk persuasively, and recite doesn't mean someone is possession of the three higher knowledges or has achieved arahantship.

What is the use of mere words without the achievement of arahantship and the six higher knowledges?

With no experiences to correlate words by themselves are useless or meaningless. Different people can interpret the exact same words differently.

It seems like during the time-period when there were many arahants in the world words weren't viewed as important or significant but now that there are few if any arahants in the world words are viewed as important.

I wonder if any arahants in the world with the six higher knowledges exist. For those who learn without a teacher it's just the same as becoming a pacceka-buddha.

Is there any reference/citation saying that Buddhism or Buddha's teachings will last only 5,000 years after Buddha's Mahaparinirvana?

Below reference were written before 500th in the Ancient Atthakatha.

The contexts about Buddhism's Existing Period Counting appear as 3 tenses in Aṭṭakathā:

1. The existing enlightenment of the current Buddha's follower (45BBE - about 5,000 BE):

Buddhism's existing period counting of current Buddha according to Vinaya.A. (samanta.3) Bhikkhunikkhandhakavaṇṇanā, An.A. (manoratha.1) Dutiyapamadadivaggavannana:

1st 1000 years after Gotama, Current Buddha, died:

Arahanta with Four Analytical Knowledges still occur=>

2nd 1000 years after GotamaSambuddha died:

Arahanta with Six Higher Knowledges still occur=>

Arahanta with Three Clear Knowledges still occur=>

Arahanta via Insight-only still occur=>>

3rd 1000 years after GotamaSambuddha died:

Anāgāmi with Four Analytical Knowledges still occur=>

Anāgāmi with Six Higher Knowledges still occur=>

Anāgāmi with Three Clear Knowledges still occur=>

Anāgāmi via Insight-only still occur=>>

4th 1000 years after GotamaSambuddha died:

Sakadāgāmi with Four Analytical Knowledges still occur=>

Sakadāgāmi with Six Higher Knowledges still occur=>

Sakadāgāmi with Three Clear Knowledges still occur=>

Sakadāgāmi via Insight-only still occur=>>

Final 1000 years after GotamaSambuddha died:

Sotāpanna with Four Analytical Knowledges still occur=>

Sotāpanna with Six Higher Knowledges still occur=>

Sotāpanna with Three Clear Knowledges still occur=>

Sotāpanna via Insight-only still occurs until the end of final 1000 years.

2. The previous KassapaBuddha (uncountable millions of years ago):

KassapaSamBuddha's, previous Buddha's, Buddhism existing period counting appear in Di.A. (sumangala.3) Sampasadaniyasuttavaṇṇanā; It using the past tense verbs). And Saṃ.A. (sārattha.2) Saddhammappaṭirūpakasuttavaṇṇanā, which connects to that Sampasadaniyasuttavaṇṇanā:

1st 1000 years after Kassapa, previous Buddha, died:

Arahanta with Four Analytical Knowledges still occur=>

2rd 1000 years after Kassapa, previous Buddha, died:

Arahanta with Six Higher Knowledges still occur=>

3th 1000 years after Kassapa, previous Buddha, died:

Arahanta with Three Clear Knowledges still occur=>

4th 1000 years after Kassapa, previous Buddha, died:

Arahanta via Insight-only still occur=>>

Final 1000 years after Kassapa, previous Buddha, died:

Pāṭimokkha memorizer still occurs until the end of final 1000 years.

3. The current Buddha's living time (45 - 0 BBE):

The sequence of existing enlightenment of the Buddha's followers just in current alive buddha's time, not died, appear in Saṃ.A. (sārattha.2) Saddhammappaṭirūpakasuttavaṇṇanā.It's explaining the Buddha's answer to KassapaThera's question in Sutta. Saṃ. Ni. Saddhammappaṭirūpakasutta:

"What is the cause, lord, what is the reason, why before there were fewer training rules and yet more monks established in final gnosis, whereas now there are more training rules and yet fewer monks established in final gnosis?"

At alive GotamaSamBuddha's time after he has enlightened, at the beginning Arahanta with Four Analytical Knowledges still occur. As time went by Arahanta with Six Higher Knowledges still occur Arahanta with Three Clear Knowledges still occur. As time went by Arahanta via Insight-only still occur. As time went by Anāgāmī still occur. As time went by Sakadāgāmi still occur. As time went by Sotāpanna still occur. As time went by Sīpavanta still occur.

(I copy from my answer because it's too long.)

How can this be possible if more people like to learn more about Buddha's teachings and Buddhism?

A short term of all above Buddha's periods are up and down depending on the situation, but it tends to go down in long-term of every period. It's something like this:

Cr. wikipedia

Is there any weak point in Buddhism or Buddha's teachings that it is going to cease to accept and learn any more by people because that particular point is no longer adaptable by current/future generation?

No, there isn't. Tipitaka has all aspect inside from the easiest to the hardest study, so the Buddhism has all kind of people inside from the fools one to the genius. The weak point is peoples' passion, not Buddhist teaching. And we need Buddhism because of peoples' passion.

When Tipitaka is going to lost people will try to reserve it. Don't be worry for the losing. Focus on the meditation. It's the best way to keep the Buddhism go to 5,000th.

It could be related to moral principles, rules, disciplines, as well as concepts and ideas.

In one situation, it may be the weak point, but it may be the strong point in the other situations. The Buddha and his disciples already decided the middle paths for all of weak points and strong to keep the Buddhism go to 5000 years. Every effort to destroy the Buddhism was known by that decision, so it is going to 5,000th definitely.

I'm not worry in this topic because which I should be worry is "Am I practicing follow Tipitaka with the best effort?"

"The good Dhamma of penetration (pativedhasaddhammo) will last five thousand years. The Dhamma of learning (pariyattidhammo) will also last this long. For without learning, there is no penetration, and as long as there is learning, there is penetration" (quoted from the Manorathpurani in Bodhi, trans., The Numerical Discourses of the Buddha, p. 1805, n. 1747). Each millennium represents a progressive diminution in dharma attainment, passing through five stages of analytic knowledge, dry-insight arhantship, non-returning, once-returning, and stream enterering. ("Dry insight" appears to refer to attainment without jhana.)

Thus, arhants only appear for the first two thousand years of the Buddhist dispensation according to this schema. If we take this literally and accept the modern date of circa 400 BCE for the Parinibbana, this refers to the period ending circa 1600 CE. Thus, according to this schema, the attainment of arhantship is no longer possible and non-returning is the best we can hope for.

Some authorities refer to a minor cycle of five periods of five hundred years each, which will be completed circa 2100 CE, including the mappo or 'degenerate age' or millenium that began about 1000 CE. This was celebrated in 1956 based on the erroneous Theravadin Buddhist era (BE) that dates the Parinibbana to 544 or 545 BCE.

Edward Conze cites a Burmese Theravadin sutta, dated to the mid-13th century by Andrew Dicks ("Enlightening the Bats") called the An[a]gatavamsa to the effect that "when the Dispensation of the Perfect Buddha is 5,000 years old, the relics, not receiving reverence and honour, will go to places where they can receive them. As time goes on and on there will not be reverence and honour for them in every place. At the time when the Dispensation is falling into (oblivion), all the relics, coming from every place: from the abode of serpents and the deva-world and the Brahma-world, having gathered together in the space round the great Bo-tree, having made a Buddha-image, and having performed a 'miracle' like the Twin-miracle, will teach Dhamma.

No human being will be found at that place. All the devas of the ten-thousand world system, gathered together, will hear Dhamma and many thousands of them will attain to Dhamma. And these will cry aloud, saying: 'Behold, devatas, a week from today our One of the Ten Powers will attain complete Nirvana.' They will weep, saying: 'Henceforth there will be darkness for us.' Then the relics, producing the condition of heat, will burn up that image leaving no remainder. This, Sariputta, is called the disappearance of the relics" (quoted in Buddhist Texts through the Ages, pp. 49f.).

The An[a]gatavamsa also predicts that Metteyya (Skt. Maitreya) will appear before the end of the age (a vast but incalculable period of time). This sutta also refers to five disappearances: of attainment, conduct, learning, outward form, and finally the disappearance of the relics that constitutes the last stage referred to above. As we are now in the middle of the third millenium of the Buddhist era, according to this schema we are in the age of learning, which will last for almost another 600 years approximately (to circa 2600 CE).

This stage or age will be characterized by corrupt government, secularism, climate change, environmental degradation, the decline of the sangha, and the gradual disappearance of dharma from the world. (The Buddha also says in the Pali Canon that the sangha will end after about a thousand years, i.e., circa 600 CE.) This is the Theravadin schema. Other schools have different specific schemas, but all agree that the dharma will gradually decline over time and finally disappear entirely, but then be revived by the appearance of a future Buddha at some uncertain but distant time in the future.

This five-thousand year schema is also repeated in the Surangama Sutra, an eighth-century Mahayana Ch'an sutra. I am not aware of any reference to the specific period of time in the Pali Canon itself.

The significance of five thousand years may be astrological. This is very close to the period of two astrological ages defined by the precession of the equinoxes. The classical calculation is based on one degree of precession per 72 years, which would equal 4,320 years, i.e., five millenia in round numbers. (A more accurate rate of 50.27 arc seconds per year gives a period of 4,296.8 years.) Since the signs of the zodiac alternate between positive and negative polarities, two ages constitute a complete binary cycle. Karl Jaspers places the advent of the Axial Age, of which the Buddha was the exemplary exponent, in the eighth century BCE.

The Upanishads/samana movement, which deeply influenced the Buddha, may date back to the seventh century BCE. 799 BCE corresponds to the exact midpoint of the Age of Aries according to the current ayanamsa, which predicts the advent of the Age of Aquarius in 2424, corresponding to the appearance of Shambhala (global Buddhism) according to the Kalachakra. The Kalachakra appears to know the significance of the 2,500-year cycle as well as the midpoint of the Age of Aries too, as it puts the reign of King Suchandra, the first Shambhala king who requested teachings from the Buddha, from 900 to 876 BCE, and the twenty-five Kalki kings each reign for one hundred years.

Still others would date the five-thousand year cycle from the advent of the Kali Yuga in 3102 BCE instead of the Parinibbana, identifying the advent of the end of the age with the end of the 19th century of the common era. One might also interpret the prophecy concerning the appearance of Maitreya to refer to the end of the five thousand year period (i.e., circa 4600 BCE) or even the Age of Aquarius (2424-4572 CE), but these interpretations are not consistent with other suttas that place Maitreya's appearance in a distant "golden age" of humanity.

In the Vinaya (monk's rules), it is said (somewhere) the Buddha's teachings would last for 500 years (rather than 5,000 years). Many Buddhists claim this did not come true therefore the Vinaya teaching is false, for example:

The passages surveyed so far help to set into context the prophecy that because an order of bhikkhunīs had come into existence during the lifetime of the Buddha, the duration of the teachings will be shortened to 500 years (Cv X.1). Now this prophecy is surprising, since once would not expect the Buddha to do something which he knew in advance would have such an effect. In fact, the prophecy in the way it is recorded in the Vinaya has not come true, as after 2,500 years the teaching is still in existence. Even the bhikkhunī order was still in existence in India in the 8th century and thus more than a 1,000 years after the time of the Buddha.

Bhikkhu Anālayo

Apparently, this was later altered by the scholar Buddhaghosa to 5,000 years (see here).

However, the majority of Buddhists, including Bhikkhu Anālayo, seem to often interpret many Buddhist teachings in a manner contrary to the original spirit of the teachings (such as, originally, the teachings of the Buddha were to be only accepted upon personal verification rather than through mere faith in unknown things). This seems to make an argument the 500 year prophecy actually came true in respect to the mainstream Buddhist religion. This video seems to make such an argument: The True Dhamma Has Disappeared: Thanissaro Bhikkhu

That being said, the Pali scriptures are mostly still pure so they do continue to exist in their purity.

In the course of the future there will be monks who won't listen when discourses that are words of the Tathagata — deep, deep in their meaning, transcendent, connected with emptiness — are being recited. They won't lend ear, won't set their hearts on knowing them, won't regard these teachings as worth grasping or mastering. But they will listen when discourses that are literary works — the works of poets, elegant in sound, elegant in rhetoric, the work of outsiders, words of disciples — are recited. They will lend ear and set their hearts on knowing them. They will regard these teachings as worth grasping & mastering. In this way the disappearance of the discourses that are words of the Tathagata — deep, deep in their meaning, transcendent, connected with emptiness — will come about.

Ani Sutta