Season 1s are great, setup, some payoff, a bit of lead into the overarching story. Then season 2 to X. The heroes win and then lose in the final episode, cliffhanger to next season. People get bored. Final season is announced and they wrap up the show.
Part of the reason why I’m really into K-dramas now. It often doesn’t feel like it’s just dragging, but actually has nice pacing.
Weird, I feel the exact opposite about most k-dramas. Good premise but then take forever to tell their story.