"You either die a hero, or live long enough to see yourself become the villain," or, for stories, "You either end the story well, or you continue telling it until you get GoT season 8."
Or the author continues for so many books that they pass away and it has to be completed posthumously, with with Robert Jordan's Wheel of Time series.
That said, I Jordan more credit that than (the still-humous) George RR Martin, since Jordan didn't spent pages building up characters and relationships only to kill them off.
