"At some point, perhaps, no-one will have a job any more, which would mean no-one would have any money to buy or run the machines anyway, and the world economy would be forced to reboot."
I rather like to think we'd end up with some kind of universal basic income and a barter system. All our needs would be provided for by the robots, but we could spend our time freely doing what we liked and exchanging stuff we produce as a hobby for other stuff other people have produced as a hobby. A bit like Iain M Banks' Culture.
I'm sure there'll be problems though; we don't want to end up with a universal basic income as depicted in James SA Corey's The Expanse, for example. Still I don't see robots making us all redundant as a particularly scary thing - after all machines have been taking our easier chores away for years; wouldn't it be nice if no-one needed to work unless they wanted to?