Odds of nirvana

If you imagine each person being cut in a particular unique fashion from the top layer through to the innermost subtle layers - worldly attainments, physical features, egocentric charms, personality attributes and ethereal qualities - then the realised one has, in some sense, chipped off the rough edges that come from being exposed to the cycle of samsara leaving behind a smooth, resistant-free surface. Since we are all cut differently, we all take a very different journey experientially and in length of 'time' - conventionally speaking.

Therefore, the odds of attaining enlightenment are determined on the quality of your cut, what you've been exposed to, what sankharas you've brought from previous lives - essentially all the factors that perpetuate the illusion of separation, many of which are bound together as a belief structure. Stacked high and weighty, those beliefs press down hard on the six sense experience. Having said that, some people's 'cut' are already partially smoothed off. As such, their belief structure is quite flimsy, and those people tend to have a high functioning ego, meaning that their degree of emotional intelligence is such that it doesn't take much for them to 'get this' - I've met these people, and they're wonderful to work with!

However, even this smoothed-out analogy no longer holds true at a certain point as one even transcends any associations with the wisdom that naturally ensues from such a position, which is illustrated in the heart Sutra as 'there isn't even any wisdom to attain'. Hence, as soon as the words are delivered, they are gone, but in the time-referenced mind those words linger for the benefit of whosoever applies themselves. One is then left with the life force that keeps the body going and the various functional tensions that come from that life force, which the Buddha described as ...'there is only this modicum of disturbance: that connected with the six sensory spheres, dependent on this very body with life as its condition.'.

Just to clarify, it's not possible to give an odds value in terms of the global population to something like this. You either want it, or you don't. Incidentally, everyone actually wants it, but they don't know that, yet.

I would submit that the question and any possible answer given can have no useful meaning. To ask who might have a better chance, Adolf Hitler or the 14th Dali Lama, might have an answer. To ask what are the odds you could attain it, might have an answer. But achieving of full enlightenment is an individual effort based on the person who is trying to achieve it, their internal efforts toward it, and commitment to the path.

Maybe a million people living now can; maybe just one; maybe none. My assertion is that this is not an “odds” question/answer. As @ruben2000 said, no statistics exist or could possibly exist.

Given this, 100% or 0% or anything in between would be equally valid/invalid – and totally useless – answer.

I find it hard to read SN 56.45 as the Buddha's saying that the task is almost impossibly difficult. Instead I interpret it as saying that it is greater, more worthy of admiration (and of practice), than the skill with an arrow that was being reported. He redirects Ananda's attention, away from admiring the youths' activity and onto understanding the four noble truths. Similarly I think that SN 56.47 and 56.48 isn't meant to be saying how impossible it is: instead it's what a fortunate opportunity this is.

Piya Tan writes that the theme of these suttas is, "The human state is rare; seize the moment for awakening":

• SN 56.45
• SN 56.47
• SN 56.48

With all due consideration,

If by odds, it is implied that enlightenment is a matter of luck, there are 0% odds for one to reach it, since progressing on the path that leads to the eradication of suffering is not a matter of chance, but a process based on decision making and causality.

In terms of it being likely to happen in the sense of a possibility, if the noble eightfold path is treaded upon correctly and completely, and there is no trace of attachment left, the likelihood of attaining Nibbana is 100% for anyone taking up the endeavour.

For a thorough explanation of what Nibbana means, how it is reached and how it is described once it is reached, please read the answer written for specifically this purpose: Can you explain "nirvana"?

Respectfully

It's very rare and extremely difficult to become fully liberated in this lifetime, though we do not have statistics.

“What do you think, Ānanda? Which is harder and more challenging: to shoot arrows from a distance through a small keyhole, shot after shot without missing? Or to take a horsehair split into seven strands and penetrate one tip with another tip?”

“It’s more difficult and challenging, sir, to take a horsehair split into seven strands and penetrate one tip with another tip.”

“Still, Ānanda, those who truly penetrate suffering, its origin, its cessation, and the path penetrate something tougher than that.
SN 56.45

Blind is the world;
here only a few possess insight.
Only a few,
like birds escaping from the net,
go to realms of bliss.
Dhp 174