I have multiple friends who made it all the way through residency and have since stopped practicing within years of "graduating. The OP describes the profession much better than you do, as a whole.
Double booking patients, requiring certain revenue targets, massive amounts of useless paperwork, etc. Considering the varying ranges of where they took up residency I'd say this is endemic industry-wide. Also jives with my personal experiences with the medical field.
Big companies have more people doing billing alone than doctors themselves. Pretty clear cut case that regulation is the enemy of efficient markets.
The issue is that doctors work for insurance companies and that means you need to do things a certain way they like while matching the way they practice and document their medical decisions.
I could explain more since I am part of one of these startups :)