While I agree that we have to respect the physician as a business person, this is a fine line. Physicians certainly should help push products to patients that need them, and I think they should disclose any significant incentives they get for pushing products.
The reason they are different is their trusted relationship with the patient. It is like a lawyer. You trust your lawyer to provide you with objective advice that is in your best interest. This might include recommending a company or service, but you don't expect their judgement to be clouded by incentives.