Every single large server in this federation has at least one Star Trek community. There is even an entire server dedicated to Star Trek.
Not only that, these communities are some of the most active I've ever seen. There is no other franchise I know of that dominates the federation as much as Star Trek does.
So, what's the correlation with Lemmy and Star Trek? Why not other sci-fi series? Please, are there any connections?? Is this all coincidental?
I think it fits. Perhaps in Europe the fan base is less large. Star Wars, Harry Potter, and even Dune are what people around me are into. Though it's mainly (only) just Star Wars.
How do you define mainstream? Sure it has to vary with demographics etc. But if you ask any random person, "have you ever heard about Star Trek?" , you will get a yes for an answer in too many cases, even if they've never watched it. Show them images of the characters and they'll likely go "aahhh yes those". Compare that to something more obscure like "have you ever heard about Aeon Flux?" and you'll probably get weird looks even though there are comics, a movie and an animated series of it. Star Trek may not be as popular as other franchises, but it is mainstream imo.
I can talk about Star Wars and basically everyone I know has a lot of context. Most people have watched a good amount of it. Even people who are explicitly not nerds know about it. Same with most comic stuff.
Meanwhile Star Trek is still a lot more niche. People know the bare basics of what it is, but that's about it. With the exception of my SO, I've met a grand total of two people who watch it.
Also if someone knows a lot about Star Wars or Marvel they don't necessarily know a lot about other nerd IPs. Meanwhile the people who knew about Star Trek also knew about shit like Farscape, Dark Matter, and other IP that just gets confused looks from most people.