So in your capitalist dream you want to limit the earnings to a socialist system amount.
no, to a capitalist amount,i.e., an amount determined by the free market which would be less than half of what they get now under the socialist system.
All Doctors are not equal. All lawyers are not equal. Good lawyers cost more than average or below average. Great lawyers cost a small fortune for every hour of their time.
Doctors are the same. Not every one of them make a ton of money every year. To get the average of $400k a year that is the doctors who earn a small fortune averaged out with several who don't.
There are perhaps half a dozen doctors in the world who can perform brain surgery if you have cancer. Those are in high demand and as a result make a lot more money than the podiatrist who is ordering the corrective shoes for those clubbed feet.
That is capitalism in practice. The best earn more than the rest.
What you want to do is lump them all together and let the market decide what they earn. But you don't really want that. What you want is for them all to be paid the least. That isn't capitalism. Walk into a Jaguar dealer and tell them you want their car for what an equivalent Kia cost. They will not meet the price. If you want a Jag you are going to pay.
Doctors are exactly the same. They won't work for less. They have student loans to pay and expenses too. They've worked hard to get there and they aren't going to settle for less.
The costs to the consumer. That would be the patients you want to screw over would be outside what they could afford. The Doctors would raise their prices not lower them. What they can charge now is limited by insurance companies that fix the usual and customary standards.
Now the Doctor who has no such limits can charge a thousand dollars for an appointment. The Doctor would have fewer patients and still make the money you want to deny them.
The principle of Capitalism is make as much as you can. It isn't to settle for less. I am a heavy equipment operator. I make six figures a year. If you decided I was making too much and wanted to cut my pay I'd just walk away. Many Doctors would do just that.