It really is hard to understand, the potential gains are enormous. If we got the pay of our doctors down to the levels in other wealthy countries it could save us close to $100 billion a year. Our doctors average more than $250,000 (that's after paying for malpractice insurance and other expenses), with doctors in places like Germany and Canada getting about half of this amount.
The barriers may not be as large in other highly paid professions (we prohibit foreign doctors from practicing here unless they complete a U.S. residency program), but the economy would benefit enormously from exposing all the highly paid professions to international competition. It is bizarre that this topic never gets raises even in pieces like this one in the NYT touting the virtues of immigration.
(We can deal with the problem of brain drain from developing countries, by compensating them for the doctors and other professionals that come here. Even if we paid them enough to allow them to train two or three doctors for every one that came here, the U.S. would still be way ahead.)