Isn't concentrating them towards high-salary fields exactly what should happen? The stated point of H-1Bs is to solve skill shortages, and fields with relatively low wages presumably have no skill shortage, or the supply/demand imbalance would have driven the prevailing wages up.
Though I love the market system in general, it's pretty clear to me that neither salary and skills nor salary and societal good are anywhere near linear (or even monotonic for that matter) across fields.
School teachers, nurses, and regional pilots are three fields I can think of where we may well have skill shortages despite fairly low wages. (in the third case, I think it's because of low wages, but no matter...)
That's because people won't pay. Those professions should be paid more, but there not because of the whim of some administrators deciding what the wage should be.
