There's a hell of a lot of selection and training (and money) involved in becoming a physician, but there are quite some monetary rewards as well... and it seems to all start with learning the difference between an alkane and an alkene. That's just bizarre, but there you have it.
(This chart is a bit unfair, in that I suspect that there are more residency/fellowship training requirements in becoming a surgeon than a pediatrician. It's a measurement of median salaries in the first year after "leaving residency or fellowship." For the record, I'm not one to begrudge physician salaries -- I think they're pretty commensurate with education/importance, etc.)