It's the mix of jazz, blues, rock and roll and poetry that made The Doors so successful. After Morrison died, it was just not the same anymore. I think that that would be the case if any of the members died first. Krieger knew how to create Spanish/oriental music, Manzarek was one of a kind keyboardist. Densmore had jazz-influenced drum beating. And Morisson was rock and roll monster with poetic heart. One of a kind band.