Earlier quoted context omitted.
I don't agree the cost of university is driving the salaries here. It's all about how many doctors are available to meet demand. If there are less, it's going to drive up salaries. There are other countries where the cost of getting a degree in a certain specialty is very low due to state subsidies but the salaries are very high once they graduate since they are scarce.
In countries with mostly free higher education doctor’s salaries are less on average than in the U.S. You really think having several hundred thousand dollars in student loans doesn’t in any way affect salaries?
British doctors, for example, work under a contract negotiated between a British version of the AMA and the British government. The government and the providers both have leverage, but the British government is the primary purchaser of services in that country. Salaries are lower since the government exerts pressure on them, as they are paid for out of direct taxation.
I understand that you feel very strongly that student debt for doctors is unjustifiable or too high or something. Student debt is not the main driver (or even a driver) of high salaries among US doctors. The level of their student debt is a completely separate topic.