Well, I'd like to add, that most people do not use social media -almost interchangeable with internet for most folks- to interact with strangers in a reddit/discord/forum fashion... they just interact with people near them i.e. Instagram/facebook and so on.
Most people are in both of one of those and they are not going anywhere and not losing users, specially instagram.
Then you have things like twitter and tiktok, which are nor going anywhere anytime soon, yes lota of people went away from twitter, but those who stayed stayed for a reason (nazis and the hard right mostly)
So in summary, the internet, imho, at least for now, is staying right where it is.
Maybe reddit will fall, since the userbase was always more techy/quirky but they still seem to be doing fine, if your are ok with bots chatting with bots.
Forgejo is already doing it