In my job, I get exposed to the owners of plumbing, construction, and other blue collar industries. From what I've seen, their houses are huge, their spouses are gorgeous, and they live in regions where they get to have an incredible quality of life.
The owner of a construction company told me once that he makes a 15% profit per year, and he charges far less than the competition because he would feel slimy taking more.
Tradesmen that can run a business and aren’t in the auto mechanics space, the oil industry, or working (vs supervising) in construction seem to do so well.
Those three are caveats based on anecdotal evidence on industry trends and manual labor injury risks.
The owner of a construction company told me once that he makes a 15% profit per year, and he charges far less than the competition because he would feel slimy taking more.