become a medical doctor
This seems awfully US centric.
Anyway, these advices aim at "higher middle class", not "rich bastard" category. Maybe apart from "marry someone rich".
Medical doctors are paid well in many places other than the US, though not as well as in the US. (For that matter, most other well-paid jobs are better paid in the US than anywhere else. Software development, law, senior management, etc.)
Also, though of course this was no part of the original question, medicine offers more confidence than most careers that your work is actually making the world a better place. (Which may not actually be the right question to ask, of course -- what matters is arguably the marginal effect, and if you're well paid and care en...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.