> Robot Mega Corp and it's owners have no need for your grandmother's scarf, so what is she going to provide in trade for her more basic needs?

This is assuming that the robots are owned by a monopoly or a cartel. Such a case is an obvious candidate for government to step in and break them up.

On the other hand, if the robots are owned by companies that aggressively compete with each other, how much do goods cost when they're made by robots using robot-produced raw materials? The more humans we replace by robots, the lower the cost of goods will be and the easier it is for charity or government to provide them gratis to the public.