Nothing that couldn't be fixed with some carefully applied lethal force (cf. french revolution).

It's all fun and games until somebody loses their head over it.

Someday they will be forced to. Its just cost of production will fall down so rapidly and to such low amounts.

Getting rich that way will be like trying to fill a terabyte scale hard drive by adding 10 byte text files. It will be a exercise in futility. Think of it more like free phone calls, unlimited internet band width and free apps.

But think about it - if the cost of labor plummets, and material costs plummet because the labor required to gather and refine materials plummets, the cost of pretty much every need and most wants are ridiculously low to non-existant. It's quite similar to the discussions about the economic impact of a molecular assembler.

Maybe not, but enough to keep their robots in repair and enough for themselves who own them to have a home/food of their own wouldn't go amiss.