With risk of being overly optimistic, you can already see signs of this happening in traditional religious communities — specifically, those having lots of children. What you’ll find is that secular communities (including secular Christians, Jews, atheists, etc) are indistinguishable in terms of fertility rate. All of them have collapsed well below replacement levels. The exceptions are non-secular, those explicitly rejecting the secular worldview and holding to tradition. You see this in every major religious group. E.g., Catholics overall aren’t above replacement level, but trad Catholics are having tons of kids. Same with ultra-Orthodox Jews, and the Amish. If you step back and look what’s happening it’s the slow death of secularism.