I fear communities are lacking resources and structure to handle the masses. It‘s something corporations already struggle with but they house like 10000 times more active users. One way to go around that was mentioned above and suggested that new users may keep creating new instances and communities so a few places don‘t just explode in size. But from my experience, if a community already covers a topic, there won‘t be much competition and we end up with a power mod environment (Reddit) at best and instances going dark from overload (hug of death) at worst.

But I don‘t want to sound too bleak about all of this. In the end these are challenges that someone might already work on.