How about Scott Baio’s decision to leave “Happy Days” for “Joanie Loves Chachi”?
They wouldn't have kept him around forever, so he took his shot. It didn't work out, but at least people know his name even today. Joanie, Erin Moran, wasn't anywhere near as fortunate (assuming she wanted to stay in show business).
There may be some spectacular cases of bad choices, but show business is so iffy that some of these people may have left just before they lost their roles. Plus, it can be hard to tell who jumped and who was pushed. Did Shannen Doherty leave 90210 on her own, or was she such a pain that she was eased out?
It seems like Chevy Chase was on Saturday Night Live forever, but he only did about one season before leaving for LA to marry somebody who lived there. The marriage didn't laugh, and I guess he had a typical SNL alumni career, but it's great for the viewing public that he bailed as soon as he did.
Not the same thing. Hat was a spinoff. And they went back.
And then he had Charles in Charge.