To be honest I'm not really sure how it works in the US, but in the UK if a doctor has passed their exams to become a registrar, they are by that time reasonably competent to practice their chosen speciality (except for surgeons). Obviously being a doctor requires a lot of practical on-the-job training but the point is the whole process is managed top-down.

Programming education is totally ad-hoc and you can be a great programmer even with a degree in agriculture.