Because of their stress levels and possible smoking/drinking/drugs? I don’t buy into “yeah they’re rich/famous but that’s a lot of stress” narrative.
In the case of a CEO of a major South Korean company, I could believe that stress could have contributed to his heart attack. But for specifically the actors/musicians category of the rich and famous, it seems like drugs tends to be a limiting factor on lifespan.
I suspect it's more of "the witch is dead/the rich is dead"