Building "reputation" and building yourself a "brand" are the worst things from the forum-era. I will not miss power-tripping mods and users with 20,000 posts writing the dumbest replies possible into every thread asking "why would you do this?", "have you used the search function?", etc. Just because you have many posts doesn't mean the posts are good. Many users ignored high-quality posts from new accounts for example.

Just because the forums you hanged around were like that, doesn't mean every forum was like that. Probably the web forum I hanged around the most on (which is where my HN username originally comes from) has strict rules about each individual post's quality (although enforced bit unevenly), and their contribution to the discussions, in one way or another. Make enough off-topic/shit posts and eventually you'll get banned because of it. The users with a lot of posts usually made well-argued posts.

Each started thread also needed a "basis for discussion" to remain open, and necrobumping was encouraged. The forum still has decade old threads actively being discussed in.

AFAIK, it's still the largest forum in the Nordics, although the moderation team (and voluntary) seem to unfortunately be shrinking rather than increasing, and the forum isn't without its controversies.

Forums aren’t all like that, as the HN comment section demonstrates. While not a full-featured forum, it would be prone to the same effects.