Think about how people won't buy turnips (or consumer goods in general) if the price is higher than they expect -- even if that's the break-even price. I think something similar's happening with employers: they won't pay more than $80-$100,000 for a programmer, the market-clearing price for programmers is somewhere around $130,000, and thus you get a STEM shortage. And this applies pretty much everywhere; it's astonishing how few employers are willing to admit that they can't fill positions, they aren't offering enough money.