The issue is that of management. The management profession has taken over hospitals and it runs those according to management practices. Overworked doctors are a result of (bad) management, and nothing else.
Except that management in hospitals are often doctors themselves (or influenced by the more senior doctors). One problem is that most doctors have gone through a residency with abusive hours - so it becomes hard to separate tradition from necessity.
I suggest you talk to some older doctors. If you did you'd discover that these insane schedules of work and training have been standard since before either of your parents were born.
http://www.latimes.com/business/la-fi-medical-resident-hours...