There are really only two options. To become fully trained in a medical specialty requires about eight years of more than full time effort (way more) after college. In this country, a potential doctor, goes way into debt and defers income for that period of time in order to train. The rewards are potentially great, but it is a hard road and often a hard life. Not many make it through.
In Europe they have plenty of doctors. There, the government pays the tuition and gives the student a nice salary all the way through their training. When they get out they continue to make respectable money as government employees and they have limited work hours. That is an amazingly costly government program. They offset it by rationing health care.
If the Europeans have plenty of doctors, then why do they have to ration healthcare?
My view is that government should not be in the business of paying for medical school. There is plenty enough money in that profession to justify going into the field without a government subsidy. The problem is not money. The problem is that the medical schools, teaching hospitals, and AMA are in charge of deciding how many people can go to medical school. And their decision in that regard is not really based on the quality of the applicants so much as it is based on their own self-interested judgment of how many new doctors we need. As you can see, they have a poor track record in making that assessment.