I feel like there are a lot of dimensions to this. I am a huge proponent of manufacturing, but yeah a lot of factory jobs suck. The problem is, they don't have to. Modern factories are way better than old ones, and could be even better if we as a culture prioritized making jobs less soul crushing rather than access to cheap shit. I also feel like people who haven't worked in manufacturing don't really understand what it's like in a modern facility. I think there's this idea that it's working at an assembly line or going out and turning a bunch of valves all the time but nowadays 99% of it is just sitting at a computer watching numbers. I wouldn't want to be on the floor at my current job but I've worked other places where it seems a hell of a lot better than most other jobs available to non college grads.

Another issue is that modern manufacturing sites are super automated. Very few people actually work at them, at least the ones in America. You can have a plant that makes millions of pounds of plastic a year that employs 60-70 people, which is less than a typical Walmart.