The issue with that line of thinking, while I think it is the optimal result, is that you have some degree of control over your future self, in setting up binding or non-binding systems for you to follow in the future. But you have no control over your past self, only your present and some control over your future. So now, you have to think of yourself as the soon to be past self, and your future self as your present self. That then goes against the authors original goal, because then you will be working forever, as the gratification is always in the future.