Yes, but that relies on an implicit assumption that you will be able to do or create enough things in return for enough things from other people to sustain you.

Yes, but that relies on an implicit assumption that you will be able to do or create enough things in return for enough things from other people to sustain you. This is no longer the case for an increasingly large swathe of the population. What are they to do once what they have to offer is no longer enough to get them to survive? For now, a lot of these people go homeless. But this trend is not sustainable, or conducive to societal stability.