What do you think will happen to the economy in the future when almost everything becomes fully automated?

As we all know, in order to reduce labor costs, manufacturing has moved from places where labor costs are high to places where labor costs are lower. But what if we take it one step further and automate everything with robots? There would be very little need for low-skilled labor if anything from apparel to electronics are manufactured completely by robots. Likewise, as automation becomes more widespread, many service jobs like cashiers and store clerks will be replaced by machines (like a robot that restocks store shelves at Walmart, for example), where only one human is needed to supervise several machines.

Will there be more skilled workers such as programmers and technicians to maintain these machines that serve us? Or will there be a huge underemployed underclass who will survive off of welfare benefits?