[gumby]

Actually your thought experiment is incomplete, so your answer is not the only possible solution.

Let's say I have a shoe factory, and I install a robot that can, say, cut the shoe leather faster, more cheaply, and more reliably (less waste). Perhaps it can cut shapes a human couldn't, or couldn't cost effectively, so I can even sell new shoe designs. The guy who used to cut the leather and put in the shoelace eyelets can now just do eyelets. This might cut my costs such that I can drop my shoe price AND make a larger profit. The lower price means I sell more shoes and make more profits. So I not only keep the old leather-cutter, but in fact might bring on more people so that I could get even more profits.

This is a contrived example, in the style of The Wealth of Nations, but it could just as well be a more complex one. Computers replaced slide rules and draftsman, yet more people are involved these days in building planes (and more interesting ones) than were in the pre-computing days.

Yes this is not the only possible outcome -- some people will be automated away, can't find other employment and they will be screwed. Governments should provide some support for them, and some governments will (probably not the US, but that's another story). But it's not axiomatic that "robots == job loss" -- we're not talking some sort of asimov robot that would be a 1:1 replacement for a human!