Not too mention the personal sacrifices they have to make to maintain a career (long hours, odd schedules, being on call, the stress of having someones life in your hands, etc).
Not to mention one mistake could cost you your entire career and all that training/money invested into education would be thrown away. And someones life is in the balance.
Pay them more by taking the money out of the hands of big pharma and insurance.
Honestly, while cost is a real factor, I don't think the number of doctors that pass the bar would increase by as much as you think. The amount of knowledge, skills, experience in that practicing physicians possess dwarves what people in many other specialized professions have. I doubt most people would have the grit and patience that it takes to cross that bar. (Disclosure/source: my partner is a physician, I am a software engineer).
That said, (only) one of the reasons for compensating physicians more is the time and money they put into their education. At least 2x - 3x more than other professions. Reduce this time / money commitment, you will be able to reduce the salaries.