Doctors earn enough in there own way and responsibility. So they don't have to go illegally in order to earn. So don't think of it this way. If you are thinking about money only, then you won't be a good doctor mentally as you will feel that you are working more than what you earn. So if you are passionate about the field go for it. Because to be a doctor you have to invest more time any other field, so your passion is the most required to be consistent in your studies.

I hope you got my point. Have a great eve!