God Himself is the one who created Israel as a nation for a mission and gave them that name. If they fail and don't behave and others fulfill that mission better what stops Him to use other people and give them that name? Both in the Old Testament and the New Testament God Himself says:
Deuteronomy 9:
13 And the Lord said to me, “I have seen this people, and they are a stiff-necked people indeed! 14 Let me alone, so that I may destroy them and blot out their name from under heaven. And I will make you into a nation stronger and more numerous than they.”
God would make another Israel out of Moses.
Luke 3:
8...and begin not to say within yourselves, We have Abraham to our father: for I say unto you, That God is able of these stones to raise up children unto Abraham.
Here He would make another Israel out of ...stones.
I have seen an interpretation that says it is symbolic and by stones He means the hearts of nations, the gentiles that were hard as stones at that point of time. It is true that the gentiles soon enough accepted Him as the Messiah, thus the new Israel, while the Israelis didn't accept Him and even crucified Him.
The first who accepted Jesus as the Messiah were Israelis studying the Law of Moses, what stops the others? Other Israelis for 2024 years now study the same books as them yet they deny Jesus is the Messiah. Answer: When Jesus saw Nathanael approaching, he said of him, “Here truly is an Israelite in whom there is no deceit.”
John 1:
45 Philip found Nathanael and told him, “We have found the one Moses wrote about in the Law, and about whom the prophets also wrote—Jesus of Nazareth, the son of Joseph.”
...
49 Then Nathanael declared, “Rabbi, you are the Son of God; you are the King of Israel.”