There were some really smart people out there working on the assembly line - accountants and other professionals. A lot of people had a second job or owned another business. The job itself is pretty mind-numbing, but if you're on a good team you can have a good time.
I thought you were going to conclude that factory workers are dumb, so you appeared relatively smarter.
(Before anyone gets upset, I have grandparents who were factory workers; I admire hard work.)