Human behavior dictates that if given incentives to work, typically you will work harder to excel and earn the rewards that go along with it. It's called the Power of Free Enterprise, and the Pilgrims first learned about this after settling in the New World.
If you remove the incentives it also removes the desire to excel. Why? If no matter how hard you work or what you do, you earn the same wage as every other doctor. You can begin to imagine the medical field will slowly decline as it gets worse and worse over time, and the it will plateau as average quality health care. That's a fact; socialism has never worked in the history of its existence. And it won't work this time, either.