I think there's a ceiling on that, too. Not saying we're necessarily near that right now, but it's possible to have two robots whose capabilities include maintaining each other. I don't think the list of possible jobs to do (both current and future) is infinite, though it could still be vast, and if technology continues to reduce the number of people needed to do those jobs, eventually we'll get to a point where there's more people wanting jobs than there are jobs available.

Though it is possible that that point is still thousands of years away.