This article and a lot of the discussion fails to make clear that there is a big difference financially between being a plumber/electrician/hvac tech and owning a plumbing/electrical/hvac business
Seems like every article that sings the financial praises of blue collar "tradesman" work fails to make this distinction. You don't become a millionaire being a plumber. You become a millionaire by owning a plumbing business. Those are two totally different things.