Calling the industry largely a scam is pretty strong. Of course for the small minority of technically competent people with interest and time it will always be cheaper to do something yourself rather than pay a business to accomplish the same thing. But most people cannot/do not want to do it themselves, and regulations are there at least partially to help protect them against the house-fire-waiting-to-happen untrained handyman.

Sure a bunch of businesses opportunistically up-charge, some I'm sure are predatory, and there are obviously efficiencies to improve, but overall scam it is not.