Even as a hypothetical that's an unrealistic question. Since we have a shortage of doctors in many regions and specialties due to price controls and educational pipeline bottlenecks, even if it was possible to rate doctors with a reasonable degree of accuracy (and in reality this generally isn't possible) some patients would still end up getting stuck with the worst performers. The only difference is that instead of the selection being mostly random as it is now, under your hypothetical the patients who would switch to the best doctors would be the wealthiest and best informed; the poor, elderly, and illiterate would continue to get screwed. Is that really the outcome you want?
Now who is being unrealistic? I accept that demand for medical services is not as elastic as in other industries, but to suggest that exposing a group of poorly-performing doctors would have no effect on their patient numbers seems rather far fetched. Even if that were the case, the sudden loss of rich patients might make a few of these doctors consider early retirement.
>Since we have a shortage of doctors in many regions and specialties
We also have record levels of advertising by not only drugmakers but also doctors and hospitals. If there is a shortage of providers, why is so much being spent on demand generation efforts?
Because healthcare industry incentives are aren't aligned to optimize for Quality Adjusted Life Years per dollar. Some procedures and drugs are highly profitable because of high demand by patients with money, but those aren't necessarily the ones that society actually needs.
