Because it's a business problem. The problem isn't that doctors don't know what to prescribe when you have an infection, it's that healthcare is so expensive that people can't afford it.
Price is way of measuring when it should be denied, because it has to be at some point. You can't spend the entire US GDP to save one life, even if it would work. At some price you have to say it's too expensive.
Then the question is, do you want to decide that amount for yourself, or have someone else deciding it for you?
if a law was passed requiring procedures to advertise the price like restaurants, it would solve most of the pricing issue. insurance systems obscure the price so the system doesn’t work.