Game of Thrones I think is one of the few exceptions to this rule. It still had plenty of story left to tell and the primary reason the 8th season was a bomb was because the showrunners were busy trying to wrap it up too quickly so they could go work on Star Wars instead. I think they could have taken the exact same half baked story ending that they had, stretched it out into ten seasons, and people would have complained a lot less. Would have been nice to have a better ending written but if they gave the one that they had the appropriate room to breathe, it would have been fine. Not great, but fine.

But wrapping that all up so quickly and suddenly is what put the nails in the coffin, in my opinion.