I was asked recently whether I thought atheism could replace religion. I said that I thought atheism could replace religion only in the sense that religion could eventually die out and then I suppose one might say that atheism had replaced it. In the absence of religion, we'd have atheism. I recognized that this wasn't really what the other party was really asking about, and so I explained that I did not think atheism could replace religion in the sense of being a viable alternative to religion or in meeting the various needs some have that are met by religion. Atheism doesn't have enough content to do anything of the sort. It is not a belief system and offers nothing beyond an answer to one small question. As far as a real substitute for religion, it seems like a poor one.
I do not regard this as a bad thing. I'd like to see the continued decline of religion, but I do not see the need for anything to replace religion. I recognize that many atheists do, and I wish them luck in finding something they consider a suitable replacement. Whatever it might be, I hope it skips dogmatic ideology and proves to be much kinder to those who want no part of it than religion has been. Otherwise, it would seem like we'd just be trading one destructive ideology for another. I think that would be a mistake.
I'll not pretend to be familiar with all the secular belief systems that have been offered up as possible replacements for religion. I suspect there are many I've never even heard of. I would be fairly surprised, however, if any of them managed to provide the sort of comfort and solace some religious believers claim to derive from their belief in an afterlife. That seems like a significant obstacle to replacing what might be the most important need currently being met by religion.