The thing about automation as it regards to economics is that it doesn't have to be anywhere near a complete solution to have a huge impact. You don't need factories full of fully self-sustained robots to cause massive underemployment.
If you can partially automate a task to the point where 1 person can do the work that 2 people used to do, you've potentially eliminated 50% of that job's market. People are somewhat adaptable, so some amount of this sort of change can be absorbed (and has historically been absorbed) as people retrain for other types of jobs, but we're quickly approaching a point where the changes brought upon by automation are going to outpace people's ability to adapt to the changes, IMO.
Absolutely true. I think when people say that robots are going to replace low-skilled workers only the uninformed are imagining an entirely self-sufficient factory that only has one door that the raw materials goes into, and another door that the product comes out of.
What we really should be imagining is a factory floor where instead of 50 people on an assembly line, or instead of 20 waitstaff at a restaurant, you only need one or two guys who know how to replace parts on the robots
If you can partially automate a task to the point where 1 person can do the work that 2 people used to do, you've potentially eliminated 50% of that job's market. People are somewhat adaptable, so some amount of this sort of change can be absorbed (and has historically been absorbed) as people retrain for other types of jobs, but we're quickly approaching a point where the changes brought upon by automation are going to outpace people's ability to adapt to the changes, IMO.