I had discussed this at length weeks ago when I talked about advanced robotics and the sheer ability of automation these days.
Before ~1750 everyone was certain that poverty was inescapable and that a human could only do ~X amount of work. From 1750-Pres we've been certain that human capital can always be moved into new markets, as irishpat says. If everyone was wrong then, they can be wrong now/in the near future.
I'm of the opinion that we will see unemployment rates for the uneducated get higher and higher, and the conservatives will have a ton of cognitive dissonance trying to balance "unemployment = laziness" and "market solutions are best." I'm also of the opinion that "uneducated" will mean different things; in 1600 if you could read, you were educated. In 1900 if you graduated high school you were educated. Today, you basically need a masters degree.
Simply saying, we're getting to the point where we can see how entire industries can be automated from start to finish. We're also getting to the point where intelligent computers are supplementing and lawyers, professors, and even doctors. One day, they will replace. It goes in three steps: complement, supplement, replace. Various markets are at different stages, but there is no doubt that we are seeing the threshold of "what can be automated" go up and up and up.