Yeah, this was a bizarre stereotype. I know dozens of doctors very well (comes with my line of work), and my BIL is a doctor. Financially, there's a HUGE range, depending on whether they are a GP, surgeon or specialist, how many hours they work, how large their patient roster is, if they are a specialist, what the modality is, how long they've been practising for, where they are practising...etc.
Plastic surgery for example, pays VERY well if you are good and establish a reputation (see: Dr. Haas). Most GP's in comparison, do not live lavish lifestyles (at least none of the ones I know), and even within specialties that pay well, what your case turnover rate is dictates how much you pull-in. Some can handle huge caseloads and rip through them like a machine, others can't. A Radiologist that sits down and can rip through 150 cases in a sitting makes 3x what one that does 50x in a sitting.