Hard to compare, the "high-income" specialties are either brutally intense (e.g. neurosurgery, cardiac surgery, vascular surgery), competitive (plastics, derm, radiology) or both (ortho).
The competitive ones are variable with ~50-80% match rates for US MD graduates. Generally hard to get employed in desirable markets (especially NYC, LA, SF, Boston) unless you trained around there so the "desirable" programs are harder to match to but numbers aren't released. Some residency programs are toxic dumpster fires.
Attrition is hard to gauge because once you're in you're kinda stuck due to loans, sunken cost etc. Completely made-up but I would consider any of the intense specialties to represent at least the top 10%ile of physicians for a combination of aptitude and work-ethic/masochism.
The competitive ones are variable with ~50-80% match rates for US MD graduates. Generally hard to get employed in desirable markets (especially NYC, LA, SF, Boston) unless you trained around there so the "desirable" programs are harder to match to but numbers aren't released. Some residency programs are toxic dumpster fires.
Attrition is hard to gauge because once you're in you're kinda stuck due to loans, sunken cost etc. Completely made-up but I would consider any of the intense specialties to represent at least the top 10%ile of physicians for a combination of aptitude and work-ethic/masochism.