[NoNameHaveI]

There are 2 reasons a show are cancelled: #1, and the reason in the majority of cases: not enough people watch. It doesn't matter if you think the current season of The Simpsons is good, terrible, or whatever. It only matters that you watch. If few enough people watch, it WILL be cancelled. This is NOT public access or PBS. #2, the artist's discretion. Rare, but occasionally an artist decides to "go out on top". Jackie Gleason and "The Honeymooners" comes to mind. Seinfeld too. I'm sure there are others you will point out.

Point is, keep watching and they'll keep pumping out crap.