> Roofing is an incredibly simple job to learn for instance, and it pays little better than minimum wage.
I can't speak to your area, but doing roofing on tall houses/buildings with a steep slope here pays much better than working on relatively flat roofs or one-story houses.
Skill does tend to get some reward; I think I'd be inclined to go electrician if I had to. I think if one wanted to get paid the most, I'd look at plumbing because it both takes some skill (despite the "3 rules" joke) and is literally shitty. Personally I enjoy a bit of carpentry work now and again, but my skill is nothing compared to my brother, and he was never really able to put together a comfortable living despite his ability. Fortunately, he was able to get an engineering job (not the software kind) fairly recently and was amazed at the idea of getting paid for a day off once in awhile and having health insurance.