This salary stuff makes the comparisons extremely murky. Professors on average make less money than successful commercial real estate brokers- a career which in many places does not even require a four year college degree. So I’d be very leery of using salary as a proxy (or even a factor) in dissecting intellectual rigor. The most gifted student in my Classics program (PhD from the top program in the world by some measures) probably makes 1/4 of what I do-- which in no way diminishes her intellectual gifts compared to mine which are quite modest. But I work in corporate America and she works for a non-profit institute which protects and preserves the material artifacts which are being destroyed by terrorists in that part of the world and we can all imagine how lucrative a career THAT turned out to be.
Salaries track to career choices- some of which are voluntary (an MIT grad working for NASA vs. going to a hedge fund; a Stanford grad working at an educational reform think tank vs. Google) and some of which are not (it is hard to go from University of New Haven to an M&A job at Goldman Sachs).
And quite frankly, some salary outcomes are completely disassociated with academic rigor- the wide and well trod path from a bunch of “country club” type colleges to careers in sales for example-- or some of the preppy colleges and the path to private banking. These are kids who find a discipline where they can log respectable B’s and C’s, join the right frat, play lacrosse, and emerge with a diploma and a job in hand. Or the helmet sports crowd who major in whatever it is that their coaches tell them to major in which won’t interfere with training, practice, and travel to games.
The smartest people don’t usually end up making the most money and I think that’s good for society. Love him or hate him- Justice Scalia was not a stupid man. If he was interested in making millions he’d have died while working as a partner at a white shoe law firm, not a public servant. Take a look at the long list of Pulitzer winners, Guggenheim’s, etc. These are people with vast intellectual gifts, most of whom are working in universities and think tanks NOT startups and private equity shops.