The market for STEM professionals is superstar economy similar to the market of comedians, athletes, musicians and artists. The payout in the profession follows Zipf's distribution.

btw. 12% of US millionaires are educators. http://www.barrons.com/articles/SB50001424053111904370004577...?

The Economics of Superstars Sherwin Rosen The American Economic Review Vol. 71, No. 5 (Dec., 1981), pp. 845-858 https://www.jstor.org/stable/1803469?