It has nothing to do with the system; private, public, Medicare, Obamacare, Aetna, Athem, or cold hard cash, it all comes out the same. That's because of who gets paid and how much they make.
From that august medical journal. the New York Times:
If you look around the world, lots of countries have single-payer systems. And all of them pay substantially less for health care than we do in the United States.... So how could a single-payer system here still be so expensive?“
The big thing is that providers here make quite a bit more money than they do anywhere else, and in order to get in the ballpark of where these other countries are, you’d have to reduce payment rates to physicians to much, much lower levels...” “...That’s just hard to do.”
....the United States pays substantially higher prices for doctors, hospital stays and prescription drugs than the rest of the group. Medicare pays less than the United States average, but not enough less to make up that difference.
The average salary for my specialty? $350,000. The approximate number of cardiologists in the greater metropolitan area in which I live? More than 100. The approximate number for a similar population in the UK, where the average cardiologist makes 280,000? Twenty.
So before the Bernie bros get too excited about a single payer system, they had better reckon with the realities of a profession that;s had it very good for a very long time, and that isn't likely to give up that privilege without a ferocious fight.