I've heard of most of these, just by... osmosis?

I became aware of the existence of fandoms rather late, already in my mid-20s, and barely missed the era of 'zines.

There are fanzines still -- check out https://efanzines.com/ -- but as the fandom ages, the number shrink, and it is a shadow of its former self. Younger fans are usually not interested n the print medium as a hobby, and want to make videos or become a self-absorbed hot-air "commenter."

The paranoid hyper exclusivity of fanzines has definitely helped them avoid the attrition of spam and the sandpapering of general public attention. But turns out to have drawbacks.

There's some odd equivalents I think. Some BBSes of the 80's, and internet forums of the 90's, also had an ephemeral collection of artists which are barely documented/remembered now. And probably by other forgotten / dwindling means. Webrings were once a thing. Mailing lists. All of them sandpapered out of existence as they became too accessible for their own good. (Though webrings are trying to make a comeback, as search engines are evolving back into uselessness...)

What the hell is one to do. You want attention, but not **that** attention... How to make a closed community, which doesn't evolve into a self-limiting clique?

Generally the problem with fanzines was that it was almost impossible to gain readers, and the publishers were almost desperate to attract them, offering subscriptions and even taking out ads in the pro SF & F magazines. The rates were absurdly low, so it wasn't all that costly. Most fanzines never appealed to all that many readers. They published largely personal or anecdotal material, while the sort of reader who would pay to subscribe wanted to find out what Robert Heinlein ate for breakfast, or why Roger Zelazny wrote a book based on Ancient Egyptian mythology. Such zines could become very popular, with up to thousands or readers, but there was only so much space for such zines -- there was usually only three or four that better than broke even at any one time. The rest of us fanzine publishers/writers/artists (and I was all three), were satisficed with a couple of hundred readers, never made a dime, and published whatever the hell we wanted. But the general difficulty of such zines attracting any attention at all meant that we were not generally subjected to the same temptations and subsequent pitfalls.