Do we? Please educate me then. I have a few guesses, the primary ones being artificially limited numbers of doctors, the artificially inflated cost of a medical degree, and the elite status that doctors hold.
A runner up guess is that Americans have the delusion that modern medicine has a near perfect solution for every problem, so doctors do not factor in cost when prescribing treatment, even when extreme costs are associated with marginally better outcomes. The funny thing about this is that because of the extremely high cost of modern medicine in practice, prescribing treatments that have the best health outcomes at the present can cause years, decades, or lifetimes of poor health and hardship due to the burdens of debt and stress. If I had to pay $10 grand for some stitches that I could do myself (which is a fairly common amount for say, 30 stitches), that cost would decrease both my life expectancy and my personal happiness.