I don't think that conflict of interest is perhaps the best way of putting it. For example, should a doctor who owns stock in a pharma company be permitted to prescribe their drugs? If they do should they be required to disclose that information to patients? In reality, I think that many doctors, through clinical experience, develop preferences for what works best for most of their patients most of the time, remembering that not every treatment works well for every patient. Many doctors, through experience & knowledge sharing, prescribe drugs "off label", for conditions not originally tested for when first allowed on the market, but through experience been  found to be helpful to patients where there are no good alternatives. .That would be called the practicing the "art of medicine". Rapid advances in drug therapies have made industry involvement a necessity in continuing medical education. Making good Drs like Dr. Stern much  needed. That is reality.