There are many forums for specific communities: specific car brands, sometimes even specific car models, watches, keyboards even (!), etc.
I'm on forums like these and they're doing totally fine. And if anything with the recent Reddit SNAFU the last thing users there want is for some central authority in SV to decide what they're allowed to talk about.
Ah, interesting. To be clear, I also meant for specific communities: like for specific hobbies or tabletop games, or niche interests.
They've all abandoned forums and, regrettably, moved on to Facebook or Discord. I'll never understand why they choose Discord, a closed chat platform, for forum type discussions. At this point I feel like Quixote tilting at the wind mills.
There are a LOT of niche forums out there that are not FB/Discord, and keeping track of them is a pain. I do wish newsgroups were still a thing for hobbies.
The trick is finding these, especially with today's crippled search engines. But indeed, it tends to be subject-specific forums rather than general-interest.