Probably true. But also true is that it takes a whole hell of a lot of time to reach the point where you can be qualified for these careers. Four years of college, four years of medical school, plus five years of residency. That's 13 years before you're finally a radiologist making real money. For most people, that would be age 31, maybe 29 or 30 for the overachievers. By contrast, someone can be an airline pilot virtually right out of high school. I was at a major airline by the time I would have been a second year med school student if I had gone that route. The lost earnings, plus the cost of med school, would probably never be overcome by the higher starting salaries in those fields. Unless you believe that major airline salaries are going to continue to drop significantly, then being an airline pilot is still a pretty quick route to good money with the upcoming retirements.
But here is the thing, and I'm sure you'd probably agree.
It isn't all about the money. I am fairly certain that if your only goal was money you'd run out of patience for the medical education. I'm certain that if someone gets into flying for simply the money (relative ease of good money vs. medical education, etc) it would still be disappointing and eat someones lunch. My point is, there has to be a passion beyond the money (for most people).
I would disagree with the idea that the lost income, debt, etc would not be overcome. $750k annually is a pretty good "hurdle jumper" in terms of income - thinking basically for every year you work, that is equal to the vaunted "six figure job" 7 times - it catches up in a big hurry. Or, with SWA Capts making $350k - it is still twice that...every year.
That said though, nothing will work right unless there is some kind of passion beneath the money. Maggie spoke to the Dean of the UMKC Medical School who is a friend of mine. She laid out to Maggie what it is like, etc, etc and they even put together a plan that, based upon Maggie's curriculum at High School, will have her done with undergrad and medical school at 23 - but Maggie is indeed a freak. The idea I'm trying to get through is that unless she's passionate about it, medical school won't work - being a passionate cosmotologist would be a superior QOL than a dispassionate doctor. What troubles me about the OP is the use of absolutes - "IT'S THE ONLY THING I CAN DO!!!1!". It's probably age talking, and this is for other younger members and not the OP - because he's already too far gone - but when you are dead-set on one thing - a thing that is by nature discriminatory (health wise, very unforgiving of life mistakes) on top of the other difficulties, to the exclusion of other things - then you are making a tactical error. I'd be a bitter ALPA goon

right now flying for some airline if my health hadn't failed me in my early 20's. Fortunately I was able to adjust my goals and I'm now a bitter businessman fighting off the unwashed masses and treating my people as motor oil - but my point is, for everyone thinking of this - Flying is neat, but have a back-up plan and please don't blind yourself to other opportunities either.