My brother works as an inventory clerk in a small-town factory in the midwest that makes small batches of custom metal parts sold to other factories. He has been there several years and is one of the more skilled employees, and makes just under $18,000 per year. No retirement or profit sharing benefits. The work conditions are unsafe, with lax enforcement of safety policies for forklifts, stacks of containers, cleani…
I'm more skeptical about not being in a free labor market. I know many people in London who get by on the minimum wage (~16K). I doubt the cost of living in a small-town factory in the Midwest is comparable to the cost of living in London.
It's a shitty situation, sure, but it sounds like a far cry from not being able to change jobs because a single day without any income would lead to insolvency.