So, after all of the stuff that Charlie said about love and the such with the near-death experiences, I had this idea that maybe there can only be one version of each person in the timelines in order for things to work out. I mean that only whenever there is only one version of each character in the respective timelines can the "true" reality be reconciled, with an amalgamation of the best, most redeemed versions of the characters we have come to know and love.
Maybe that is why Charlie said to Jack, back in LA X, that he should have dide. He understands that he had to die in order to reach this shangri la of redemption.