"However, if you want to become the best plumbing contractor in Bemidji, that is probably doable by two-thirds of you."

Is that because being a successful plumbing contractor is easier than being a good tennis player? Bullshit. A plumbing contractor doesn't make over a hundred bucks for walking through your front door because it's "easy". A tennis player only has their own play to worry about, whereas a plumbing contractor has to have a lisences, bonding, insurance, vehicles, machines, a supply house, a shop, and workers including journeymen, helpers, laborers, and even a secretary to worry about. They have to use good social skills to develop a clientele base, and logic to submit competitive estimates. They have to complete every job on time and within the agreed on budget or they don't make a profit. And how many women are plumbers let alone plumbing contrators? It's not more than a handful in the whole country and that is because it's not only complicated, but hard and dirty work. If a person can't lift and set an assembled commode, they can't do it.

Someone can have a PhD from Harvard, and it is absolutely meaningless when it comes to this kind of work. They can only learn how to do it through lots of experience, and formal training is only helpful with the building code part of it. The assumption that certain work is easier because it's practioners wear coveralls is again, bullshit. Someone is naturally a better plumbing contractor in the same way that someone can naturally be a better tennis player.