@Hey Jude What you are missing here is that John's relationship with Yoko DID NOT break up The Beatles, no more than Paul's relationship with Linda broke up The Beatles. In my opinion, the nail in the coffin was Brian's death, because that meant they had to start dealing with the business side of their relationship with each other themselves.
While Brian was worried about whether his management contract would be renewed, I don't believe that they would not have resigned with him. As John said immediately following his death, "He was one of us." And as he reflected in ...