The plumber wasn’t making that much though. That $300/hr includes a lot of buisness costs - someone needs to pay for the fancy van they drive in, the office workers (which is often private equity backed and has a lot of office staff and CEO that you don’t care about), advertising, and whatever other costs. Plus the plumber often only has 20 minutes of work in your house, but between jobs taking an unknown amount of time, and drive time to the next job they need to charge for a lot of time that they are not working.