If Israel is the vine that prefigures Jesus, the "true" vine, isn't Israel's purpose fulfilled?

Romans 9-11 addresses this issue head on. The conclusion is found here, in Romans 11:25-28:

25 I do not want you to be ignorant of this mystery, brothers and sisters, so that you may not be conceited: Israel has experienced a hardening in part until the full number of the Gentiles has come in, 26 and in this way all Israel will be saved. As it is written:

“The deliverer will come from Zion;
    he will turn godlessness away from Jacob.
27 And this is my covenant with them
    when I take away their sins.”

28 As far as the gospel is concerned, they are enemies for your sake; but as far as election is concerned, they are loved on account of the patriarchs, 29 for God’s gifts and his call are irrevocable. 30 Just as you who were at one time disobedient to God have now received mercy as a result of their disobedience, 31 so they too have now become disobedient in order that they too may now receive mercy as a result of God’s mercy to you. 32 For God has bound everyone over to disobedience so that he may have mercy on them all.

If you look at the unfulfilled prophesies in Scripture, you will see Egypt, Syria, and several other ancient kingdoms mentioned. God still has future plans for them, for good or ill. Lilkewise, there are unfulfilled prophesies concerning Israel. God will fulfill them. Therefore Israel has not ceased to exist as a party to God's blessings, curses and prophesies. Indeed, the late Ellis Skolfield demonstrated how two of Daniel's prophesies predicted the rebirth of Israel in 1948 and its recapture of Jerusalem in 1967 to the exact year. If such ancient prophesies of Israel continue to be fulfilled even at this late date, will not the rest also be fulfilled?

Then Paul and Barnabas waxed bold, and said, It was necessary that the word of God should first have been spoken to you: but seeing ye put it from you, and judge yourselves unworthy of everlasting life, lo, we turn to the Gentiles.

For so hath the Lord commanded us, saying, I have set thee to be a light of the Gentiles, that thou shouldest be for salvation unto the ends of the earth. [Acts 13:45,46 KJV.]

Paul made it very clear in Antioch (in Pisidia) that salvation is by the Gospel of Jesus Christ and that if anyone (Jew or Gentile) rejects that gospel in unbelief, if they 'put it from them' then they have deemed themselves 'unworthy of eternal life'.

So saying, he shook off the dust from his feet (Acts 13:51) when he and Barnabus were expelled from the coasts of that place by the persecution of the Jews.

Again, at Corinth, when the Jews opposed themselves and blasphemed, Paul shook his raiment, and said :

Your blood be upon your own heads ; I am clean. From henceforth I go unto the Gentiles. [Acts 18:6]

This is hardly the behaviour of a man who expected the Jewish people to be gathered in, at some future event, as Jews, in some separate kind of in-gathering other than the repentance and faith set forth in the gospel.

What was demonstrated in Israel, in the wilderness and in the temple, was an everlasting testament, (Hebrews 13:20) and that everlasting testament was inaugurated with the blood of Jesus Christ.

Once the everlasting testament, in reality, was founded in the sufferings and death of Jesus Christ, then all that was old - passed away (2 Corinthians 5:17).

If any man be in Christ, says the apostle, he is a new creation.

The individual Jew, who believes in Jesus Christ, is become a new creation.

But if anyone, Jew or gentile, rejects this gospel, they have rejected eternal life.

The fulfilment of all that was set forth in Israel, is the redemption that is in Jesus Christ.

If the fulfilment be rejected, then the whole purpose of the setting forth is nullified. It becomes pointless. That is to say, it is nullified and pointless in regard to the one who rejects it.

If I pay an architect to make a model of the building I want to be built, then once the building is built, I dispose of the model, for the reality stands before me and the reality was the point of the whole exercise.

I don't pay the architect the agreed fee and then attempt to live in the model.

But if the architect is agreeable then she may marry me and we can share the new building together. And we can keep the model in a cupboard, just as a fond memory of our introduction.