Small "we focus on interest X, we retain with comment sections and we monetize through ads" websites got killed a decade ago by facebook that centralized that model to their site. If you want to do basket weaving or local HEMA re-enactment group or anything in between in your area, your state, your nation, etc, there's a facebook group for that now. That is vastly superior in connecting people and generating good articles that aforementioned websites ever were, which is why facebook won.
Then reddit killed the actual forums in the exact same way. It's both better and more convenient to have a centralized depository for everything, with common interface and rule set from perspective of 95% of users (I pulled that number out of my ass, but you know exactly what I mean).
What's left is mostly various wikis, and similar "we provide information" websites. Those are getting hammered by AI being able to answer faster and better than having to go through a wiki for a few minutes for that specific interest you're looking for. This is notably why google is losing profitability. It's bread and butter was monetizing the search that found those sites, and then monetizing their ad stream through google ads that were common on such sites. Today, google's AI search is better at answering those questions (not to mention just asking questions of other popular models), but on top of that if your AI answer to the question being asked is on point and answers the question user is searching the answer for... you don't get to monetize it nearly as well.
But the hilarity is that internet is more alive than ever. It has more actual users than ever, as older generations who don't use it are dying out, while newer generations basically live their entire lives on the internet the way older ones couldn't even imagine. But with people being more and more able to specifically select for their more and more specialized and narrow interests, those of us used to much broader communities with broader interests are left with a feeling that everyone is gone.
Meanwhile every football guy and every party girl is in fifty snapchat/whatsapp/discord/etc groups that have to be muted because otherwise the phone wouldn't stop going off with notifications from other people in those groups talking.