4 pane comic of dolan on the left and spooderman on the right
pane 1 (dolan): cum join opensurce cummunity!
pane 2 (spooderman): shure! how joyn?
pane 3 (dolan): Here discord! (with discord logo)
pane 4 (spooderman with tears in eyes): y u do dis?
By this do you mean official forums? If so I think this is kind of missing some of the independent forums for software (whether games or media players or the like) or other media, which some sorta-everyday people set up in the past. Many have migrated to Discord not only because it's easy but, I think, because it's simply more cost-effective.
Forums don't seem to be cheap. Discourse's own managed hosting goes for $50 a month, from one of their partners it's $20, and looks like somewhere in-between if you try to spin it up yourself (e.g. Digital Ocean droplet runs $4 a month, then add in domain, and mail-provider (~$20-35)). Looking at that, it's little wonder so many either opt for official forums, unofficial subreddits, Lemmy/Kbin communities, or Discord servers instead now.
Maybe if I dug around some more I could find some options for managed hosting (which makes more sense for regular people, I think, to deal with technical maintenance) for Discourse or the like that are cheaper, but I can't imagine one may find much that beats free. Unless there is something, unfortunately I guess we're kind of stuck with the situation as-is barring some pleasant exceptions.
Yeah, I was referring to official forums for technical support or feature requests and the like. I don't really think that everyday people were usually the ones who setup forums, it is website operators and other techies who set those up. The people who setup an independent forum are not the same people who setup a discord community. Discord has a much lower barrier to entry that usually results in a lower quality information and moderation than a forum would.
I mean, yeah, forums are harder, for sure. $20-35 monthly for a mail provider seems to high to me; I would expect that to be about the yearly cost. But, I don't really have much experience with an email provider for that use case. Really the problem lies in that a website operator and a community maintainer are 2 very different types of people that rarely intersect.