In most cases, the buyers will decide whether he buy or not but...

I both agree and disagree. A doctor's office, lab, or hospital is the one that sets the price of medical care, but a patient is still able to refuse or "shop" around. My husband desperately needed an optometrist appointment due to his glaucoma and this was at a time when we didn't have insurance. I called every optometrist in the area until I found the lowest price. Also, I've refused tests that I knew weren't necessary in order to save money. Switching to generic brands saves money. Looking at different insurance plans allows you to find the best deal for your situation, and so on and so forth. So, while the physicians do decide their cost of care, patients still do have rights and the ability to make their own decisions.

I work for a doctor. To me it seems that the Insurance determines the care-expenses more than the doctor. We get letters from the insurance companies that can deny or accept the prescriptions that he writes. We also have to have the insurance approve of most of the specailists we may want to use. Almost everything revolves around the patients inusrance. And if you don't have insurance, its harder to get someone to see you if you're going to a specailist.