That's literally the first time I've ever heard anyone challenge that "theory".

Also, there are significantly harder degrees. Many engineering schools have insanely hard tests where upper echelon SAT types get 20, maybe 30% right. The results are then graded on the curve, with the median being a C. Other classes more aligned with other majors even at the same college could see almost all A's and B's for everyone.

This shouldn't devolve into a "my school can beat up your school" or whatever. But some schools and some majors are significantly harder relative to a given GPA and that is an iron clad indisputable fact that I've never heard anyone even attempt to challenge before.