God has never forsaken Israel as per Romans 11.
Rom 11:1-5 NKJV I say then, has God cast away His people? Certainly not! For I also am an Israelite, of the seed of Abraham, of the tribe of Benjamin. (2) God has not cast away His people whom He foreknew. Or do you not know what the Scripture says of Elijah, how he pleads with God against Israel, saying, (3) "LORD, THEY HAVE KILLED YOUR PROPHETS AND TORN DOWN YOUR ALTARS, AND I ALONE AM LEFT, AND THEY SEEK MY LIFE"? (4) But what does the divine response say to him? "I HAVE RESERVED FOR MYSELF SEVEN THOUSAND MEN WHO HAVE NOT BOWED THE KNEE TO BAAL." (5) Even so then, at this present time there is a remnant according to the election of grace.
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Rom 11:28-29 NKJV Concerning the gospel they are enemies for your sake, but concerning the election they are beloved for the sake of the fathers. (29) For the gifts and the calling of God are irrevocable.
Paul makes it clear collective Israel's blindness it temporary and gentile believers should not be ignorant or "wise in your own opinion" of this.
Rom 11:25-27 NKJV For I do not desire, brethren, that you should be ignorant of this mystery, lest you should be wise in your own opinion, that blindness in part has happened to Israel until the fullness of the Gentiles has come in. (26) And so all Israel will be saved, as it is written: "THE DELIVERER WILL COME OUT OF ZION, AND HE WILL TURN AWAY UNGODLINESS FROM JACOB; (27) FOR THIS IS MY COVENANT WITH THEM, WHEN I TAKE AWAY THEIR SINS."