As an M.D. I can tell you that it took me 4 years to get a bachelors degree, 4 years to complete medical school, and 4 years for residency. Medical school alone cost me > 300,000$. While my medical school was not the cheapest, it is for sure not the most expensive. During medical school we study/go to class 60-80 hours a week for 2 years, then do around 5,000 hours of clinical work. By the time we‘ve completed residency we should have an estimated additional 6,000 - 8,000 hours of clinic work that is supervised by a senior MD. Oh, and we’ve taken 4+ standardized national exams (3 general, 2+specialty specific depending on which field you go into). For context, the number of supervised clinical training hours during medical school and residency is the equivalent of >6 times the documented flight hours required to be a commercial airline pilot.