Lawyers study as long as Doctors, get as many loans, and make less. Most Law School grads make under $50k. Vets are worse. It's harder to get into vet school then MedSchool, the coursework is harder (you have to know medical care for multiple organisms), the loans just as bad, and $50k is a really good salary for a Vet. Hell do you think ANY humanities PhD is ever gonna pay off his student loans?
I would have a lot more sympathy for American Doctors if their foreign counterparts didn't make do with a much less pay. Luxembourg is an incredibly expensive country to live in, yet their Doctors make 30% less then our doctors. Yeah we overpay our MBAs, and MPHs, but it's very hard for me to sympathize with a guy who does the exact same job as a Doctor from Winnipeg for $40,000 more and complains he isn't paid enough.
I disagree as your facts appear to be incorrect.
1. Lawyers have 3 years of school and no residency. Doctors have 4 year schooling, 4 years of residency, and more residency if they specialize. Cardiologists often don't finish training until their mid-30s. I don't follow how you say they study "as long"? They aren't even close to similar.
2. You're not comparing properly. In Canada med schools are far less than the US ones. About 1/3 less according to the article. Thus, the society subsidizes some of the costs of their training. So they don't have large loans with interest to pay off which enables them to be paid less...