Well, I think the main worry is that there won't be any more jobs for humans.
There are plenty of people who want to have more stuff. I don't think that the constraint for building more stuff or providing more services is that we don't have enough raw materials.
I'm not sure I'm following the analogy. If robots replace humans, we will have an increase in things to buy due to increased efficiency, but a lot more people will become poorer due to a lack of empolyment. If no other factor is involved, what you'll see is at least an increase in the disequality of distribution of richness between those who have been replaced and those who owns the replacement, proportional to the level of sophistication of the said AI.
If it's worth saying, but not worth its own post, then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should start on Monday, and end on Sunday.
4. Unflag the two options "Notify me of new top level comments on this article" and "