Religion is necessary but not sufficient for morality. So I agree with the poster that loss of morality was partly caused by loss of religion. But Christianity itself changed from a good religion to a bad religion in the 1800s in America, so that was another problem.
I stumbled on this thread in a google search. I am not a physical survivalist, but I am cultural survivalist in a sense and I believe that good religion is the key to cultural survival. Of course it doesn’t hurt physical survival if you are part of a religious community where people can trust each other.