You don't think there might be a certain information asymmetry between you and a medical care provider? And if there's not, why are you going to doctor at all?
Regulatory reasons. Even if there was pure info symmetry (a unicorn itself), I can't "prescribe" treatments for myself even to address well-known ailments, such as the case with anyone with a chronic disease or infection.
There is an information asymmetry when I buy an apple at the farmer market. That doesn't mean that every time I buy an apple I'm getting ripped off by the seller.
If you feel the value of your life/health is essentially comparable in gravity and scale to buying an apple at a farmer's market, your opinions on healthcare regulation are unlikely to be relevant to very many people.