You know, that's a very good question.
The dispensation of the Jewish nation has ended with the cross. They served their purpose in the redemptive plan of God and are no longer a covenant nation anymore. So, regardless of who is ethnically Jewish, they are no longer a people to God, apart from Jesus Christ.
I disagree.
[Rom 11:1-2, 11-12 NASB] 1 I say then, God has not rejected His people, has He? May it never be! For I too am an Israelite, a descendant of Abraham, of the tribe of Benjamin. 2 God has not rejected His people whom He foreknew. Or do you not know what the Scripture says in [the passage about] Elijah, how he pleads with God against Israel? ... 11 I say then, they did not stumble so as to fall, did they? May it never be! But by their transgression salvation [has come] to the Gentiles, to make them jealous. 12 Now if their transgression is riches for the world and their failure is riches for the Gentiles, how much more will their fulfillment be!
Further, that Jesus' return will not occur until the Jews come back to faith in Him.
[Mat 23:37-39 NASB] 37 "Jerusalem, Jerusalem, who kills the prophets and stones those who are sent to her! How often I wanted to gather your children together, the way a hen gathers her chicks under her wings, and you were unwilling. 38 "Behold, your house is being left to you desolate! 39 "For I say to you, from now on you will not see Me until you say, 'BLESSED IS HE WHO COMES IN THE NAME OF THE LORD!'""
I say "back" to faith in Jesus because the Jews were the originators of faith in Christ.
[Gal 3:6-9, 16 NASB] 6 Even so Abraham BELIEVED GOD, AND IT WAS RECKONED TO HIM AS RIGHTEOUSNESS. 7 Therefore, be sure that it is those who are of faith who are sons of Abraham. 8 The Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, [saying,] "ALL THE NATIONS WILL BE BLESSED IN YOU." 9 So then those who are of faith are blessed with Abraham, the believer. ... 16 Now the promises were spoken to Abraham and to his seed. He does not say, "And to seeds," as [referring] to many, but [rather] to one, "And to your seed," that is, Christ.
Salvation by faith alone apart from the Law originates with Abraham's covenant of faith 430 years before the law of Moses was given. It is a Jewish covenant. The ONLY way to qualify for salvation is to qualify as a descendant of Abraham. The Jews are the natural "branches" of that family, but Christians are the grafted in branches of that family tree. Yet - God has not rejected the Jews for it says:
[Rom 4:9-13, 16-17 NASB] 9 Is this blessing then on the circumcised, or on the uncircumcised also? For we say, "FAITH WAS CREDITED TO ABRAHAM AS RIGHTEOUSNESS." 10 How then was it credited? While he was circumcised, or uncircumcised? Not while circumcised, but while uncircumcised; 11 and he received the sign of circumcision, a seal of the righteousness of the faith which he had while uncircumcised, so that he might be the father of all who believe without being circumcised, that righteousness might be credited to them, 12 and the father of circumcision to those who not only are of the circumcision, but who also follow in the steps of the faith of our father Abraham which he had while uncircumcised. 13 For the promise to Abraham or to his descendants that he would be heir of the world was not through the Law, but through the righteousness of faith. ... 16 For this reason [it is] by faith, in order that [it may be] in accordance with grace, so that the promise will be guaranteed to all the descendants, not only to those who are of the Law, but also to those who are of the faith of Abraham, who is the father of us all, 17 (as it is written, "A FATHER OF MANY NATIONS HAVE I MADE YOU") in the presence of Him whom he believed, [even] God, who gives life to the dead and calls into being that which does not exist.
So lets look at this covenant or promise God made to Abraham:
[Gen 17:4-10 NASB] 4 "As for Me, behold, My covenant is with you, And you will be the father of a multitude of nations. 5 "No longer shall your name be called Abram, But your name shall be Abraham; For I have made you the father of a multitude of nations. 6 "I will make you exceedingly fruitful, and I will make nations of you, and kings will come forth from you. 7 "I will establish My covenant between Me and you and your descendants after you throughout their generations for an everlasting covenant, to be God to you and to your descendants after you. 8 "I will give to you and to your descendants after you, the land of your sojournings, all the land of Canaan, for an everlasting possession; and I will be their God." 9 God said further to Abraham, "Now as for you, you shall keep My covenant, you and your descendants after you throughout their generations. 10 "This is My covenant, which you shall keep, between Me and you and your descendants after you: every male among you shall be circumcised.
You must see this promise (the covenant of salvation by faith) and say that A) the way to inherit salvation is by becoming a descendant of Abraham, and B) that it is an everlasting covenant (a dispensation without end), and C) that the land of Israel and Jerusalem is promised as an everlasting possession of the descendants of Abraham.
There are still ethnic Jews, but they are in the same condition as the Gentile. They are no longer a distinct group, they have become enemies of the New Covenant (as all men without Christ are) unless they repent. They are of the world, and the world is against the Church - the true people of God, that has lived throughout all ages.
They should, by now, realize that God has finished Israel's existence. I mean, despite the fact that God has allowed them to forcefully steal a chunk of the land through conflict that they no longer rightfully own, they haven't set foot on it for nearly two millennia, that's the longest diaspora they have ever faced. God hasn't spoken to them by prophets since then until now and still hasn't yet. God didn't speak to them about a return, like he did in the past. God didn't prepare their return, as he did in the past. They have possession of less than half the land, the other half belonging to sovereign state of Jordan (which they cannot interfere with). I noticed that before every return from exile, the people are repentant. We do not see a spiritual revival among the Jews since the beginning of this statehood. They have become more secular than before! The Messiah hasn't arrived still yet. They do not know what tribe they belong to. They live in an age where animal sacrifices would be internationally denounced, and to keep the Law they must slaughter animals in droves for all sorts of prescribed commandments written therein. The Golden Dome on Temple Mount prevents them from properly building another Temple. Muslim population exceeds limits that prevents them from being wholly a Jewish nation that implements Jewish law. Must I go on? Who are the Levites? Who are the priests within the tribe of the Levites? Who is the direct line of the High Priest to take on that role? Tradition holds that some people are, but where is the heavy documentation that Ezra required after the Babylonian exile? He would not permit, by God's command, just as the Law says, anyone to act as priest without documentation.
There is so many obstacles that clearly show Israel is no longer meant to function as an ethnically covenant nation anymore.
Again, I disagree. God has guaranteed the promise to both lineages of Abraham... the natural seeds (Jews) and the adopted seeds (Christians). As Pslam 69:28 says, the Jews are ALREADY written in the Lambs book of life (because they are born there), but if they do not believe in Christ, they will be blotted out. Unlike Gentiles who are not born with their names in the book of life, but rather are written there after their adoption into the lineage of Abraham.
If God told us about the natural things and we didn't believe, then how will we believe the spiritual things? The Jews are the natural branches, and if they believe they can be grafted back in the same as us... but they are grafted back in as natural branches, not as wild branches. It will be required before Christ will return... and He will not return until it is accomplished.
[Rom 11:19-27 NASB] 19 You will say then, "Branches were broken off so that I might be grafted in." 20 Quite right, they were broken off for their unbelief, but you stand by your faith. Do not be conceited, but fear; 21 for if God did not spare the natural branches, He will not spare you, either. 22 Behold then the kindness and severity of God; to those who fell, severity, but to you, God's kindness, if you continue in His kindness; otherwise you also will be cut off. 23 And they also, if they do not continue in their unbelief, will be grafted in, for God is able to graft them in again. 24 For if you were cut off from what is by nature a wild olive tree, and were grafted contrary to nature into a cultivated olive tree, how much more will these who are the natural [branches] be grafted into their own olive tree? 25 For I do not want you, brethren, to be uninformed of this mystery--so that you will not be wise in your own estimation--that a partial hardening has happened to Israel until the fullness of the Gentiles has come in; 26 and so all Israel will be saved; just as it is written, "THE DELIVERER WILL COME FROM ZION, HE WILL REMOVE UNGODLINESS FROM JACOB." 27 "THIS IS MY COVENANT WITH THEM, WHEN I TAKE AWAY THEIR SINS."
At some point, the dispensation of the Gentiles will end and God will return his attention to the Jews. It must happen before the end. God is not done with them yet. The time of the Gentiles started with Pentecost when the Spirit was given to the church. Many have prophesied that this year - 2020 - in which we've had a real Passover where the Plague of the Wuhan Virus began to diminish on Jewish Passover - and for the first time since the original Passover in Egypt, all of Israel were shut up in their homes on Passover - many have prophesied that the real Passover would be followed by a real Pentecost... in which the Spirit of God will fall on the earth as it did at the original Pentecost which birthed the church. Does this mark the end of the age of Gentiles? I don't know. Maybe.
Consider there are 24 elders in Revelation... 12 disciples of Christ, and the 12 sons of Jacob. Both sets of descendants.