I appreciate the optismism of “build it and they will come” but i think the true frustration behind “fandoms are dying” is a multi layered problem that making more content will not fix because:
a) puritanism, bullying, purging of content, and antis are on the rise. especially of nsfw art.
“But i don’t want nsfw art” you say. “I only want pure, good art/fic thats full of happy puppies and kitties”. tough tits. you cant nurture creativity in a fandom thats constantly gatekeeping. thats how you get “dead fandoms”.
b) giant corporations are co opting fandoms in an attempt to make [even more] money. this feeds back into point a (of course disney doesn’t want queer/adult content, they’re advertisers/investors would disapprove) and therefore antis feel more empowered to bully and harrass.
Now lets say you DO post your nsfw slash art on twitter. Its basically the wild west. Anybody can find you, attack you, bully/harrass you and, again, because of points b + c these harassers all think they have a right to do so.
SO. “Make more content for your fandom” is a nice sentiment except there’s nowhere to post, no one to like it, and everybody is so goddamned scared of death threats and being cancelled they either don’t make the content to begin with or people don’t reblog/share because “what if the creator is secretly a bad person and i didnt know it and now other people think im a bad person”.
Fandoms are dead because the water is toxic. Dropping more stuff into the water won’t help. You gotta clean up the water first if you want creativity to thrive.