My guess is it was a trend started by Jump animes, trying to plug up as much running time to fill a half-hour time slot while not messing with the pacing of the actual show material. And then, since that's the way it was done, shows started competing over having the best intro, leading to really fucking bangers that no one really wants to do away with, and now we're here.
I forget the anime, but they used Radiohead’s “Paranoid Android” as their intro song.
I loved that!
Kinda related, the Star Trek Intro songs are pretty good too, but the series “Star Trek Enterprise” had a godawful song. I don’t want that series as much, because I just don’t want to hear that song at the start of each episode.
It's honestly my favorite. The other ones are great, but faith of the heart is amazing.
New Trek's intros are too long, tbh. I like them, but they're way too long, and paramount plus never gives me the option to skip, so they get irritating if you're binging.
Buffy's was also amazing, but ent still takes the cake for me