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.
It depends on the show.
In some cases, shows are written to be anthologies of stories. The characters stay similar across episodes and seasons, but the isn’t really an overarching plot. Sitcoms are known to use this a lot. Plot across episodes is mainly done to give writers something new to write.
In other cases, several plot lines are happening at once which resolve at different times. That way, there is always a plot having something happening even if other plots end or hit a resting point. A lot of soap operas did this.
Finally, there can be one overarching plot that gets resolved, but then another plot starts to take its place or the show ends. A lot of modern science fiction is written that way.
@HobbitFoot
@delitomatoes Many sitcoms have an overarching romance arc between two leads that gets stretched out for eternity. I don’t know how much I can vouch for “The Office” handling other storylines, but the getting Pam and Jim together 1/3rd of the way through the series, and then not having them constantly breaking up and dating other people and then getting back together (like Friends) was a real breath of fresh air. The show really proved they could survive as an anthology without having the main romantic arc to fall back on. Of course, later on they introduce serious romantic arcs for other characters.
I don’t look at it like an overarching plot so much as anthology. Character A and Character B have chemistry and should be together but it doesn’t happen. It just happens that there are several stories that involve that failure.