You're trained in something because you love it. You really want to do it, and you went to school for it, have experience in it. Someone gives you a choice -- you can do this for $XX/year or you can starve. The labor market is not as "free" as free-marketers make it out to be. I made a mid-career switch from social work to coding in part because of compensation, but it wasn't a friction-free switch. Also, my point was in response to the above poster who claimed that engineers were getting a fraction of what they deserved. By your metric, programmers are also getting what the market values them at. But by OPs metrics, I maintain that teachers create a lot more value than someone building another ad-tracker.