I remember the cast of Friends wanted to stop after season 8 I think.

Then they got offered $1 million per episode along with residuals.

It’s not just corporations that want to keep things going. The actors actually “unionized” (so they all got paid the same amount) and agreed that they wouldn’t continue the show unless they all wanted to.

How I Met Your Mother got to the point that Jason Segal wanted to leave. The last season was just awful and you could tell that he was phoning it in.