I agree this would represent the end of the current socioeconomic system, and that many/most would not enjoy the neo-feudalistic-at-best system that would replace it.
The robot factories don’t require consumers as inputs. They don’t necessarily vanish if the consumer economy vanishes. (I agree they would vanish if you tank the economy in, say 2027.)
So next step, business go bust, because there is just not enough billionaires to keep all of them alive. Another step is states go bust because there is no income to be taxed and there is no capital exchanging hands in buying goods which could be taxed.
I mean systems in which there're no expectations of giving something in return for getting something of economic value. That which happens naturally within family.