Your first statement is what non-teachers tell teachers when we start asking for a fair deal in the job. "You picked that job. You knew what you were getting into. Stop complaining." It defeats the purpose of this entire post and what you said about the AC guy is exactly what "Careful" implied about teachers.
As for the stop complaining because we make more than an AC guy.... well that's not true. If their skills are needed and the price of equipment rises, then they can charge more. Which in turn allows them to take more home. (If you have a non-crappy boss). If they own their own business as an AC guy then they definitely get to set their prices. And if they are good and in demand then more money goes home especially this time of year.
Schools have always been worked liked a business (whether that's good or bad, I don't know). But people that go into business are taught that if after year 2 you haven't gotten that pay raise you deserve, bargain to other companies and get that pay raise somewhere else. Imagine if teachers started thinking that way (which some do/have). Then teachers would be leaving kids every 2 years for their rightful benefits, but how does that benefit the kids? That MIGHT work for core teachers if they only teach one subject AND grade level. But as elective teachers building programs, leaving every 2 years because the business(school) is choosing to treat us poorly, that won't build anything.