It's highly dependent on the demographic I think. I'd guess that I'm younger than you based on your comment about having kids, and everyone in my social circles use Facebook messenger or instagram.
Interesting, my kids all have 20+ large iMessage groups for their friends at school. They play Minecraft and Among Us while on FaceTime calls. They are in the 8 - 11 year range. So it is certainly down to demographics, but perhaps not age