Both of these fields have a non-trivial amount of people earning excess $1M a year.
It is really hard to come up with a useful average when including with History PhD's and Dermatologists as part of the same cohort.
The averages aren't that misleading though, since they represent the average choice of degree. If you know you're going to study history, then yes the numbers are too high for you, but the averages are correct for the average person.
You're right that a non-trivial number of professional advanced degree holders making more than $1M/yr. There are also many scientists and engineers and business people doing the same. People making more than $1M/year are statistical outliers, as are history PhDs in the U.S.
https://www.statista.com/statistics/185353/number-of-doctora...