Doctors are far less geographically mobile than many other high income earners given the time required to establish a practice and licensing issues. As such, the threat of leaving the country is much less credible than for, say, a higher earning financier or entrepreneur. If the top tax bracket is too high (I think it is), it should be an issue that all high earners grapple with together.

If doctors don't make enough money, argue for a raise rather than side perks like the tax-free accumulation of savings and income sprinkling.

As to the risk involved in being a doctor -- this is fairly low. Demand is insensitive to the economic cycle, the supply of doctors is artificially restricted by the government and we as patients have little transparency into the merits of one doctor vs another

It seems like a stretch to describe many doctors as businesses when they exclusively bill one payer -- the government. Tax regulations normally prohibit people from incorporating when in this situation