imo: same reason why most people don't host their own mastodon server, or their own website, or their own e-mail server: it takes time and money to maintain these sorts of things and it's easier to make it reddit or discord's problem.

imo: same reason why most people don't host their own mastodon server, or their own website, or their own e-mail server: it takes time and money to maintain these sorts of things and it's easier to make it reddit or discord's problem.
forums do still kinda exist. they just usually serve pretty small communities of people. i'm on several creative writing forums that are pretty neat.
Seconded. I regularly visit (at least) two forums. They're just much more rare, unfortunately.
Also related to that, community continuity on those platforms is much easier to maintain, if the person who's been running things loses interest or runs out of energy for the (lesser but still there) volunteer labor of it or whatever it's much easier to pass on admin privileges to someone else versus all the hoops it would take to transfer ownership and control of a self-hosted forum site, even if there was someone else willing to take on the labor and costs.
And even if you do have to start over from scratch it's a lot less ask to get people to join a new subreddit or fb group or discord server w/e with their existing account versus creating an entirely new account with an entire new website on trust that whoever's running the new one will be around long enough to make it worth your time...
I miss forums too and to one degree or another hate pretty much all the service platforms that have replaced them but I do get it :/...