I'm really curious to see if we start to see separate instances dedicated to separate topics like that. Imagine that forum you used to participate in on its own instance with all the same subforums/categories. The difference now is that you can federate that niche forum with the wider fediverse if you want to engage with a larger audience.
People are used to that singular reddit feel. I never started new posts on reddit because I would rarely get a response. If nobody catches your post in the new section of a semi-popular sub within an hour or so, it's gone. Or on a large sub, I had a post removed for being too similar to other posts even though a search didn't yield any results. When I asked which post it was similar to, I get a snarky comment from a power tripping mod about "not being a librarian" and muted for a week so that I can't respond as punishment for daring to question them. Come to think of it, reddit is kind of a shitty place with the exception of a few niche subs.
Now, I'm feeling much more inclined to start new threads since I feel I'd actually be able to have a conversation here.