Is someone killing actors , or their characters , to change how movies or shows end?

I find that when an actor or actress makes a good movie that they suddenly die, or their characters. As if to prevent future movies. Batman Joker, Heath Ledger. Dead after a great movie. Edna Krabappel ,Marcia Wallace, after marring Ned Flanders. Carrie Fisher after making the latest star wars movie. Han Solo’s character dies and then Harrison Ford lives. It is just off the top of my head. Please add more to the list. Humor and insight welcome. Conspiracy theory answers welcome. Or you can just humor me. Also Leonard Nimoy and Captain Kirk. Are the Fates screwing around with us?