Those users indeed don't matter. The problem is the cool kids are on Twitter & co as well these days. Because that's where they have the most reach. Almost everyone on social media cares about reach, there isn't much of a point to posting things that no one reads.

The old web was a very different place, it wasn't as centralized and there were significantly fewer people around. There were specific forums that you'd go to for specific topics. Say you were interested in West African dances - there was usually the one forum where all the West African dance nerds hung out. At most a couple of different ones. And they were very small communities. If there were issues with the admins or moderation users could and did do mass walk-outs and create a new place.