Japan never really had a God and did quite well for a time. If anything they were becoming more and more Christian as their economy declined.
India believes in hundreds of Gods and they're doing quite well right now.
The Islamic world believes in God, and some say the same God as Christians, but if not for oil they would still be penny ante nomadic tribes.
Those countries were not founded on a Christian world view and Christian principles. So they were never blessed like our nation, who, in its beginning, openly and universally acknowledged its dependence on God for all things.
The difference could not be greater.
God, and specifically a universal general belief in the Lord Jesus Christ is what resulted in our nation being unique and exceptional. That is a fact. Every principle embodied in our Constitution came from the Bible.
Those other nations may be prospering materially, but have never prospered spiritually. I’m referring primarily to the moral and spiritual decay of our nation, not the material.