Probably more to do with America's economy booming and a massively growing population in earlier 20th century and joining in WW2 after everyone else. The previous superpower was pre occupied with a Roman Catholic called Adolf Hitler. And developing the first atomic bomb helps considerably too.
If it ewas to do with religion, Spain and Italy would be up there as well, but guess what. They're BUST.
If it ewas to do with religion, Spain and Italy would be up there as well, but guess what. They're BUST.