Look at any prediction from a century ago that religion would fade out, and it missed something: religion adapts. It changes music, language, and structure, but it keeps offering things people still want, like meaning, ritual, and community. The other side can point to falling attendance in parts of Europe, and that's fair. But that's decline in one form, not disappearance. Globally, religious populations are often growing, and even in secular places people rebuild spiritual practices. So by 2100 I'd expect religion to look different, not gone.