But even the general public and mainstream media don't care that much about Science Fiction.
Not necessarily. Look at the top-grossing movies for the last few years. AVATAR, THE HUNGER GAMES, HARRY POTTER, PIRATES OF THE CARIBBEAN, the STAR WARS prequels, THE AVENGERS, IRON MAN, the last STAR TREK movie . . .
SF/Fantasy is practically mainstream now, especially when it comes to summer blockbusters. And look at all the mainstream media coverage the San Diego Comic-Con gets every year . . . .
HARRY POTTER - FANTASY (There's absolutely not science involved)
THE HUNGER GAMES - CREATIVE SPIN ON REALITY TV (No one considers this Science Fiction that I know of. I guess you could say that because they use technology to create/manipulate the "game" that this makes it Sci-Fi (which is setting a low threshold for what makes Sci-Fi), but I wouldn't call it Sciene Fiction, and I don't most people see it that way. And how they actually get technology to create an entire forest and alter it at will is not even attempted in terms of explanation/plausibility. We're just supposed to believe that "some time in the future" this can happen. That's more fantasy to me than anything.
PIRATES OF THE CARRIBEAN - FANTASY (Absolutely no science is involved.)
AVATAR - FANTASY/sci-fi (The upper/lower case is on purpose. The Na'vi are beautiful, fantastical, aliens in what seems like a magical world. The fantasy/love aspects of this story take over the science aspects overwhelmingly, and I'd suppose this is by design.)
STAR WARS - FANTASY/SAGA (There are tech things, like light sabers, that are used, but they may as well be powered and designed by magic for as much scientific explanation they get. And magic is used with "the force" and all that.)
THE AVENGERS/IRON MAN - SUPERHERO MOVIES (There are both some fantasy and sci-fi aspects to these films, but I'd say that the superhero film is a "type" of film, and these movies are more that than anything else.)
STAR TREK - SCIENCE FICTION/fantasy (The upper/lower case is on purpose. This is a science fiction movie, but there's no scientific basis for a couple of things, like Vulcan Mind-melds... That's more a fantasy element.)
I think the recurring theme here is FANTASY, not sci-fi. And no one ever said fantasy wasn't popular, at least not that I know of. It's very popular. Always has been.
All those films listed are in the same genre. It's only fans that debate fantasy vs sci fi vs superheroes and argue about how to categorize and where is space opera and all that cud chewing. It's all stories told outside of the real world and it's all in the same category as far as media and the public goes.