I am in anguish for my fellow Jews who have such outward blessing in their covenant with God, but have not come to faith in Christ.
But God's plan hasn't failed - He always chose only some from Israel for salvation, rejecting others.
Who is saved is up to God, not us.
We might object that God shouldn't blame us, then. But we are all His creatures - if He wants to punish some of us to show His justice, and save others to show His mercy, He can do that without blame.
Many in Israel sought God's favor, but on their own efforts without faith and got nowhere. The newcomer Gentiles with simple faith have surpassed them.
How this is about Jesus
He says Himself that we cannot come to God unless the Father draws us.
He was the younger brother chosen in Israel over His elders, to their anger, resentment and rejection.
We need to thank God for His mercy - that our salvation isn't up to our efforts or we'd never attain it.
Avoid blaming God for His election and salvation plan, as if we can spot holes or injustice in His plan. We are the creation, not the Creator!