I think the key word in the sentence is trying to be doctors. The doctor per pop count in very low because med schools have super low acceptance rates[1]. That would probably be the best place to implement some sort of reforms if we want more doctors.
I imagine if med schools made it easier to get through their programs, the end result would be a significant lowering of the average pay for their profession, as more doctor's hit the job market. It sounds like it's in the best monetary interest of doctors to keep their professional supply low, allowing the demand for them to be high.
[1] https://www.accepted.com/medical/med-selectivity-index