I don't think the disobedience of Israel has anything to do with our salvation. The gift of salvation was decided for us the moment we lost it through the disobedience of Adam and Eve. The Lord told us in Lev. 17:11 that God gave blood on the altar for the atonement of souls, and although Christ's crucifixion was not know of for 4,000 years, the veil has been lifted and we know that blood was the blood of Christ.Two very important points.
1. Abraham was the very most faithful man remaining amongst humanity when he was called out of Padan Aram. There were very few on the earth who even truly recalled God not to mention believed Him as did AAbraham.
2. The Children of Israel while in the wwilderness were disobedient, and by their disobedience salvation was gained by the nations.
The seonc point here is indicative of our Father's will from the beginning of creation. I believe so.
The Children of Israel were far from perfect from the beginning. Had Israel been perfect gentiles would never have gained salvation.
The true Israel, that is those who will rule with God, are all who believe Him.
What we are told to thank the Jews for is that they were chosen as a blessing to us, as the Lord used them to show His ways to all people.