It's not just pay. All that time and money that doctors invest in their training as well as the risk they take every day when performing their surgeries, writing prescriptions, administering medicine is all risk. If a CEO botches a company, he can usually get a job somewhere else and continue his career. If a doctor botches a surgery, his or her career is usually over. CEO's and traders don't have to carry malpractice insurance. The risk and opportunity cost alone justifies the higher salary. For all the people who wish that doctors were paid the same as teachers and government workers, I wish that they lived in a society where that was true.
Under a single payer, doctors may not need to carry that risk.
Perhaps that risk is because we have a fundamentally private sector system where the insurance companies absolve themselves of all potential practice by their "in network" doctors.
And not all government workers are paid the same.