Doctors are paid for the service they provide so they are incentivized to prescribe things that arent effective. This is a large part of why americans consume so much more healthcare than other countries where doctors get paid per patient on their panel. I agree doctors should determine health care prescriptions but we need to align incentives first.
I think doctors' incentives are more aligned with patients than the incentives of insurance companies. I agree that incentives aren't perfectly aligned, but I'd rather a doctor decide whether I should get a treatment than an insurance company, given the system we have.