The anecdotal evidence is widely available. For his movie "Sicko," Michael Moore interviewed a doctor in London, England, who makes a nice salary and owns a million-dollar home in a very nice area of London. A doctor on salary has no incentive to run up the costs by performing extra serivces. A doctor who generates a "fee per service" has every incentive in the world to perform larger and more-costly "services" as many times as possible. Salaried doctors lack those same incentives and are better positioned to keep costs down while not compromising healthcare quality.
Last week I was sitting around a table with friends. Many of them are on Medicare, and many of them had stories of what doctors were forcing them to do in order to maximize the income of the doctors. In one case, a person had two ingrown toenails, each of which needed the exact same minor surgery. The doctor told him that he could do one toe in November and the other toe next February. My friend asked why he could not get both toes done at the same time. The answer the doctor gave him was that the insurance company paid more if the surgeries were at least 60 days apart. Another friend needed two blood tests. The doctor scheduled him to come back on two different days. When he asked why he couldn't do them both the same day, the doctor told him that the insurance company would not pay for both tests if they were both done the same day.
In the early 1980s I traveled up to Canada as part of a business deal with a doctor in Quebec. I had a long talk with this doctor about Canadian healthcare. As a doctor, he was paid a salary of $100,000 (Cdn) for 40 hours a week working in the Canadian public health service. With inflation, I'm sure this would be a lot more today. But after he had worked his 40 hours, he was allowed to work whatever additional hours he wished in private practice, and so he joined a local private practice where he saw patients who preferred to use that system. These doctors were selling convenience and rapidity of service as their primary product, since any Canadian could obtain the same services for free from the public healthcare service. My doctor friend in Canada made so much money from those two jobs that he was heavily invested in three outside businesses, which he owned. Canada proves that you don't need to eliminate the "fee per service" model entirely, and that doctors aren't going to be forced onto poverty rolls if we prevent them from earning millions of dollars per year in "fees per service" deals.
Did you ever wonder why your doctor always seems to be so rushed when you go to a doctor's office for a routine visit? The answer is this: the more patients the doctor can see in any given hour, the more money that doctor makes. So, the incentives are all in favor of rushing through as many patients as they can manage, and not taking any real time to ensure that each patient is getting appropriate quality care. It is no wonder, then, that the costs in the United States are by far the highest, while outcome measurements are below average for Western industrialized nations (Germany, France, England, etc.).
Public healthcare in most countries is made possible in part by paying doctors salaries, thus largely fixing the cost at an affordable level, no matter what the healthcare needs of the community might be. The vast majority of people I have spoken to from Canada and England have been quite happy with the care they received for free from the public system. Yes, you can find people who have been forced into long waiting lines, but those are the odd occurrence and not the regular routine. And the reasons for the waiting lines are generally the same as they are here in the United States, such as a lack of donor organs for transplants. And quality of care is an issue no matter where you go. The system in the United States does nothing whatsoever to ensure each patient receives a quality treatment. Instead, the incentives in the United States are all in favor of higher incomes for healthcare providers while minimizing the costs of delivery to the patients, which means minimizing quality of care.