Below is my response.
I don't think the Jewish people “lost” anything as a result of Christ and the New Covenant. (The Gospel is good news for Jews too!)
As far as their “standing with God,” no Jew was ever saved by being Jewish. All people are and have been saved by grace through faith. Old Testament saints looked by faith toward Christ (the Messiah) and New Testament saints look by faith back to Him. This is the clear import of Paul's insistence that folks are truly Abraham's seed by faith, not biology.
. . . they are not all Israel who are of Israel, nor are they all children because they are the seed of Abraham; but, “In Isaac your seed shall be called.” That is, those who are the children of the flesh, these are not the children of God; but the children of the promise are counted as the seed (Romans 9:6-8).
Therefore know that only those who are of faith are sons of Abraham (Gal. 3:7).
The truth of which Paul speaks is not new to the New Testament. That is, no one is or ever was saved by DNA.
In regards to the land, God kept His promise. This is made abundantly clear in the book of Joshua.
So the Lord gave to Israel all the land of which He had sworn to give to their fathers, and they took possession of it and dwelt in it. The Lord gave them rest all around, according to all that He had sworn to their fathers. And not a man of all their enemies stood against them; the Lord delivered all their enemies into their hand. Not a word failed of any good thing which the Lord had spoken to the house of Israel. All came to pass (21:43-45).
Again Joshua says,
Behold, this day I am going the way of all the earth. And you know in all your hearts and in all your souls that not one thing has failed of all the good things which the Lord your God spoke concerning you. All have come to pass for you; not one word of them has failed (23:14).
That being said, the "land promises" point to ultimate realities in Christ and His church both now and in the new heavens and earth. In other words, Christ did not come to delay or postpone God’s promises; rather He is the ultimate fulfillment of those promises.
For all the promises of God in Him are Yes, and in Him Amen, to the glory of God through us (2Corinthians 1:20).
Thus my concern for Jews is that they come to Christ. They need Jesus more than they need real estate.