I think it's very easy for people who aren't working with their hands every day to sit back and talk about the 'satisfaction' you get. You may get that if you go and do it for a day. When you're doing it every day you're destroying your back, knees, your hands end up cut and calloused, and you're exhausted. And the 'satisfaction' probably doesn't make up for the lower pay manual labour jobs typical come with.
+ your hearing, it can be very noisy in a mine.
I'm from a coal mining region and some of the miners hate the job with passion and curse it every day as they get on the comutter's bus. Others are more indifferent about it and even enjoy some aspects of it (mostly camraderie). I'm pretty sure the majority of them would switch for ANY office job that pays the same.
My general thoughts on the "I'm unhappy doing CRUD" sentiments is that people generally tend to get bored with what they're doing and the dream of one day doing something else, something more fulfilling, relieves the pain somewhat. Funnily, for pretty much all the alternative careers that devs talk about, there are internet threads where people working those jobs are discussing how to retrain as a software developer.
It's totally different when you can barely afford your mortgage, you're in debt, and you have no chance of getting a better job.