no you have to contribute to your fandom if you don't want it to die. most fandoms die because people say 'it's so sad watching the fandom die when the hype dies' without doing anything about it. I'm not saying you have to push out 100k word slow-burn fic, I'm not saying you have to make fan art or gif sets or edits or anything. I'm just saying we as a community should contribute to our fandom if we don't want it to die, and by contributing, I'm talking about giving kudos, commenting on your favorite fics, reblogging your favorite art and just talking about your favorite characters. that's enough to keep a fandom alive. that's the most effective way to keep a fandom alive in my humble opinion.
fandoms die because people stop talking about it, fandoms die because people stop engaging with fan content once the hype is gone. what I'm saying is, mainstream media's hype may be gone, but our fandom can stay alive and thriving if us as a community don't let it die.