Everyone here saying they still exist.
That’s not the point.
The variety and quantity have all been replaced by spaces like Facebook, Youtube, Discord, and Reddit. Heck, I used to help run two gaming phpBB forums and participate in several others. They’re all gone or the groups have moved to Discord or whatever. PhpBB forums were usually run by private individuals, modded by those with shared interest, and subsisted on donations to run if the owner didn’t just pay for it out of pocket. It was still a little bit of the “old internet” where anyone could create their own slice of it for next to nothing.
I miss them because is was a concentration of each niche and there usually wasn’t much competition. No competition for “likes” or whatever. More of a conversation. If you were into something like old tractor restoration (this one still exists as a forum), you could find a wealth of knowledge in text and photo form, videos, if any, are short and generally to the point without deliberate monetization. I absolutely cannot stand YT as a “information” source because of the constant fluff generation to extend the video for adspace and groveling for subscribers. But that’s a whole different rant.
Anyway, yeah…some forums do still exist. Thankfully they’re generally pretty good at what they do. The others have vanished or moved to corporate social media platforms.