My conjecture is that most people will refuse to let go, even when their lives have become boring (at least in comparisons with possible lives lived by new generations). If this happens, there will eventually be no room for new generations. A kind of collective irrationality will lead to a bleak life for the last generation that decides to stay around. Unless we put and end to the human race (through global warming, for example), before this happens, individual egoism will block the path to a better world.