You may be physically old but your logic is juvenile at best.
Doctors have to get an undergraduate degree plus take a bunch of pre-med classes before they can even apply for med school. It’s a tough career to get into and requires, not just a lot of money up front, but a lot of time. You have to really want to be a doctor to go through all they have to to make that $300k/year salary. That’s why there is a shortage of qualified physicians, especially in rural areas.
If there isn’t the promise of making enough money to compensate for all the time, money, social life, family life, etc that they had to sacrifice, there won’t be enough of them to provide that “free” healthcare leftist politicians are promising you.
Your “they shouldn’t have to pay” fantasy is childish.