I think most Doctors etc need to wait until they're consultants until they make decent money.
But I'm like you - fell into banking due to being a Lotus Notes developer when it was flavour of the month and have never left. I reckon I'm on over double what I would be if I'd ended up working for IBM or Cap Gemini or similar.
[And I should say I ended up in project/programme/change management. I'm not still a Notes Developer]
A doctor is also a kid who got full A grades as a high school graduate. They'd have the pick of what university course to do, and then they end up doing this thing that takes until you're 30, with insane nighttime hours. It just makes no sense to me that there are still kids who think this is worthwhile. It's not even as if you are guaranteed to be allowed to specialize in what you want either, that's a battle with all the other top students.
Yes, because the number of med school places in the UK is limited by the government (because they have to fund the extra cost of the course over what students pay in tuition fees). You don't really need to be that smart to be a doctor.
A consultant gets £100k -> £140K ish from the NHS. However, many supplement that with private work and therefore make significantly more.
To get to the starting line of Consultant they have to go through the Residency gauntlet which start you off at 36k and hideous hours.