Before roughly 2000 Fantasy and Sci Fi were Weird and Shamefull according to society.
So it starts in the 1920s: Fantasy and Sci-Fi are BAD, WEIRD and SHAMEFULL to a huge degree. This is the pulp era. Stort stories, comics and magazines are printed on cheap pulp paper. There are couple hidden gems in here, but the VAST majority is beyond utter silly trash. Only kids "that don't know any better yet" and weirdos read this sort of stuff. And, objectify, most of it is beyond bad.
Things get no better in the 30s and but by the 40s you have movies and 50s TV shows....and again most are beyond bad. Sci-Fi here digs in deep to wear the badge of "silly stuff for kids". Again, couple gems, but most is just made bad...they don't even slightly try and hide it.
The 60s are mostly the same....until near the end when a movie called 2001 comes out......and a little show called Star Trek. So the whole stigma is still there....but the first cracks start. You also stared getting some good novels, out on the fringes.
Moving into the 70s, Star Trek slowly changed a lot of minds about sci fi. Even today, the best Star Trek episodes still work and stand the test of time. And Star Trek really highlighted sci fi's power for social commentary. And then came Star Wars. And it had a huge impact. Nearly every kid loved it...and some adults (my dad would endless say how he was blown away watching the first couple seconds of the over head shot of the corvette and the star destroyer...something he had never seen before in a movie). Though plenty of adults saw Star Wars a "just more silly stuff for kids". Still there was a small, but growing, sicf fantasy fan base.
The 80s! Enter me! Born a couple years before, I'm now old enough to read! And lucky for me yard sales/flea markets are full of 10 cent books: all that 'pulp' stuff written decades ago put into cheep books. I read a lot, but love the fantasy and sci fi ones the most. D&D and RPGs soon follow, as they picked up in the 80s. And there was a sprinkle of such movies and tv shows. Except the Star Wars original trilogy did not really bring many kids over to sci fi fantasy. Sure, they loved Star Wars, but that was it. But then there was not much content anyway... A typical 70s teen liked Star Wars, but then likely grew up into an 80's adult that considered sic fi fantasy weird and shamefull and though Star Wars was a good kids movie.
Until the TV shows picked up the idea that many (like me) born around and after Star Wars really liked sci fi fantasy. So they started making such cartoons: He-Man, G.I Joe(technically military sci fi), Ghostbusters, Ninja Turtles, Robotech, and of course Transformers. Now, a kid that liked sci fi and fantasy could find a lot to watch...
......and that was not all as Star Trek the Next Generation came out. A bit rocky at first, and ignored as more "silly kids sic fi", it made a name for itself after a couple years. Then you had the 80s movies...Alien(s), Terminator, Predator, and more not only caught peoples attention, but really go notices as "not silly".
And in novels there was quite a break away hit with a single character: Rastilan from Dragonlance. The Dragonlance novels were a huge hit. And then, right at the end of the 80's with another character: Drizzt.
The 90s brought more Star Trek DS9 and Bablyon 5 to start and then into Hercules, Xena, Buffy, Charmed, Sliders and more. Suddenly there was a lot of fantasy sci fi TV. More movies too, and more cartoons.
As the 90s moved on, all the kids that grew up on sci fi and fantasy became adults. And unlike older generations they did not toss sic fi and fantasy away. They stayed fans into adulthood. and they had a steady diet of TV shows, movies, books, and more. And that fan base, going back to the teens that saw Star Wars, started having kids in the 90s....
......and as a kid in the 90s they had a ton of sci fi fantasy content, and were exposed to lots of it by their parents.
Right about to 2000....when a large chunk of people, age 5 to 35(more or less), were sci fi fantasy fans. Well, this is the "buying block of people": the ones that buy the most stuff. And they wanted Sci fi and fantasy.
And companies wanted money...... So suddenly the age old Weirdness, Silliness, and Shamefullness was just Gone. After all, a huge number of people like it now....how could they be wrong?
Enter Today....