I am very biased in this stuff, I'll say that up front. I was in the "in-crowd" for multiple forums over the years, ran my own for many years (essentially a personality cult, as per your article), and so of course I have a warm and fuzzy view of the medium. Importantly, I found my time on forums to be socially stimulating. By that I mean that the interactions were strong enough that I didn't feel lonely, despite being stuck in various isolated places. I have never felt that way about the interactions I've had any other platforms, with the exception of direct IM clients.

With that preamble out of the way, something that's come up in the comments below but I don't feel has been explored sufficiently is permanence. Modern profit-driven platforms focus on transience. They are built around the endless-feed model and keeping users engaged as long as possible. This is built into their very bones - it's always about new content and discussion isn't designed to last more than a day. Old content is actively buried.

That's antithetical to the traditional forum model. Topics on a subject would persist for as long as there was interest (sometimes too long, of course) and users' contributions would form a corpus of work, so to speak. I found that forums that allowed for avatars and signatures were particularly good in this respect as they served as "familiar faces", allowing users to become visibly established community members.

I've used Reddit for 14 years (although lately I've given up on it) and not once in that time have I felt a sense of community. The low barrier of entry and the minimal opportunity cost of leaving a community makes the place a revolving door of (effectively) anonymous users. It's my opinion that a small barrier to entry is a good thing, coupled with persistence of content. It's not enough to have much of a chilling effect, but it provides a small amount of consequence to users' actions and that's arguably good for community formation and cohesion. A gentle counter to John Gabriel's Greater Internet Fuckwad Theory ( https://www.penny-arcade.com/comic/2004/03/19/green-blackboards-and-other-anomalies ).

I run a Facebook group and we have an entrance question - the answer to the question is basic knowledge for the target audience, however the question itself also includes directions for where to find the answer (the first paragraph of the Wikipedia article OR the group's rules). Most people just give the answer (and some overthink it and put a load of extra info in, because the question is suspiciously easy) but a subset of people either can't be bothered or don't even finish reading the question. In my opinion, the community we've built is better without those people.

This ties into the concept of profit-driven vs. community-driven platforms. A profit-driven platform wants as many eyeballs as possible, regardless of what the owner of those eyeballs can contribute to the community. The community exists purely to facilitate profit, something which feels to me like a terrible basis for a community.

Something I do feel OP is correct about is discoverability - that's particularly an issue in the modern era of garbage search engines. I don't have any particular thoughts on the subject, I just wanted to say "Yep! Agreed!", haha.