You're neglecting customer loyalty, and patient throughput. A doctor who (correctly) says "there's nothing I can do for you; ger some rest and you'll get better" will be seen as "uncaring" and patients will de-register from their practice. They'll also have to spend time arguing / "educating" obstreperous patients, and earn less. A doctor who writes a (perhaps unwarranted) prescription finishes the visit faster, and gets better patient reviews.

I'm not making this up. A medical provider up-thread made this point.