Even if nearly all currently existing jobs will eventually be automated, as we progress toward that point new jobs will continue to be created for humans, preventing the kind of mass unemployment or low wages that might be expected, as long as the market has time to adjust (which isn’t necessarily the case– if the pace of automating jobs were to speed up enough, we could still see a crisis.) However, once machines surpass human capabilities for a low enough price in all jobs, the entire economy will change and something else will take its place. What that is we can’t really say– our economic models break down, and the future becomes even more difficult to predict. Beyond this point, we don’t even know to what extent humans are still guiding the course of civilization, let alone how employment will work.