Inside the Actors Studio

[SpaceAnJL]

I think it is in part the dreadful business of forcing anything on past the natural span. A coherent narrative seems to be incompatible with most multi-season shows. It is all about longevity rather than the story, so plot elements get padded out, stretched thin, or outright derailed. If you have relationships involved, it seems to get even worse. And generally, an audience only has a finite amount of patience for being buggered about.