It is not completely impossible that in a moment of electoral desperation, Joseph Robinette Biden Jr will be called into a private meeting with Valerie Jarrett and David Axelrod and told that it's time for him to announce that he wants to spend more time with his family. But it's not very likely.
The chief function of a Vice President is making the President look good, and by that measure Joe Biden is one of the best vice presidents who ever lived. The rule of thumb is that the more incompetent the man at the top is, the more of a buffoon the man just below him needs to be to make him look good. And again Biden does this job brilliantly.
