I met a guy (he was around 17) who was working for a pulp mill. His job was working on a machine that debarked the trees. They would run through the machine and then appear in front of him. He had two cords ending in a button which he held in his hands. One button would send the insufficiently debarked tree around for another cycle of debarking, and the other button indicated that it was good enough and could continue.
He indicated that this job was mind numbing to the extreme but that it paid very very well for someone not yet finished highschool. If he worked there long enough his hourly pay would be actually pretty good for the rural area he was in. He told me that many people who worked at the mill never bothered to finish high school and few went to University because even with a degree it would be hard to beat a job at the mill.
I am pretty sure that I could build a bark detecting optical system in under a week to replace him if the mill were still open. But it isn't through a combination of far lower demand for paper product because of the electronic age, combined with far higher efficiencies at the existing mills.
But all one has to do is go to the early seasons of the show "How it's made" and see that even fairly automated assembly lines usually had people doing things such as quality control, packaging, and the occasional odd procedure in the middle. Now, if you watch the recent seasons, about the only thing people do is to load crap into the machines at the beginning, and forklift large boxes of the final product in the end.
One of the final job killers are the pick and place machines.