Education degrees are broadly considered some of the easiest degrees and have large numbers of them matriculating:

https://nces.ed.gov/programs/coe/indicator/ctb/graduate-degr...

They're signals with low leverage since everyone has to have them in their field, so you end up with lower nominal pay from the institutions that buy most of that labor.

Consider acceptance rate as a metric - education has one of the highest by this report, up there with public service:

https://cgsnet.org/wp-content/uploads/2025/12/CGS_GED-2025_R...