I remember hearing about sleep deprivation in the medical field before; especially for people who work in the ER or as surgeons. The demand in the US for nurses and doctors is very high, and so are the education costs which can be prohibitive to people getting into medicine. There's a whole system of failures, from the cost of education to the student loan systems to medical insurance and billing, that has led direct…
There is a "shortage" of doctors and crazy hours in countries with free education, no student loan system and insurance is ensured by the country for all citizens.
So, no, these issues are not the whole story (which doesn't mean they are not issues).