This relies on the assumption that there are things Joe wants that Bob can supply and vice versa. But as we climb higher and higher up the hierarchy of needs th

This relies on the assumption that there are things Joe wants that Bob can supply and vice versa. But as we climb higher and higher up the hierarchy of needs that may not be the case. We are already very effective at keeping people alive and mildly entertained indefinitely. (Although we currently look down on these people as trash for not contributing to society). But I can envisage a time when meeting all my material needs requires almost no human input and meeting my emotional needs cannot be monetised.