Brian's death was obviously an accident. I mean, in one year he would've run Apple (or perhaps something similar but less risky), so it's not like he would have had nothing to do. I think paul said once that it was money and business that split "The Beatles", not anything else, so brian's death was really the death of the beatles as a business.
by the way, It was the Beatles (I.E. Brian epstein/"british invasion") that began pop music as a mega marketing tool that produced millions and made music a real profitable business (Britney Spears should be thankful). before the beatles, artists went penniless once their days were done, notably in Jazz.