Lost was the first big show I can remember that just had a one to two beat opening theme.
It's weird that it took so long. Early films, the Jazz Singer if you go way back, had a fifteen minute overture, reminiscent of the orchestral opening to stage plays while people found their seats.
Movies eventually realized that, artistic merit notwithstanding, that was boring. They first shortened those intros to a card of the main players. Sometime later the guilds required credits include all craftsman, but just stars. A fair and egalitarian move with the unintended consequences of reexpanding credits, making them... Less fun. Studios just moved the credits to the end and began with some establishing scene instead, as a compromise between the contributors and audience.
I guess anyone who mostly watched things after Lost wouldn't expect long tv intros. But then, most streaming services let you skip them, so it shouldn't be a big deal