At its peak, there were probably a few hundred posters, tops
This is mostly the crux of the matter. It doesn't matter if you're talking about Reddit, phpBB, discord, imageboards, whatever. As a community grows, it becomes harder to deal with and more "faceless". I've been in great sub reddits. I've had to leave message boards on other platforms for the problems you describe (and others).
If I remember correctly trying to fix this is what killed Digg. A high percentage of their content were the same power users rushing to post content from the same well liked sites. They tried to do away with it by just dumping the sites RSS feeds into their site. Everyone fled and because Reddit didn't make those changes it became where they fled too.
This is mostly the crux of the matter. It doesn't matter if you're talking about Reddit, phpBB, discord, imageboards, whatever. As a community grows, it becomes harder to deal with and more "faceless". I've been in great sub reddits. I've had to leave message boards on other platforms for the problems you describe (and others).