I can't resist excerpting the following from The Daily Princetonian. These fine people exhibit a clear understanding of the concept of opportunity costs.
Is your economics professor who can't seem to communicate outside of the supply-demand graph equally as competent an instructor as your fluent Italian literature professor? Regardless, chances are the economics professor is better paid.
Published studies conducted at multiple universities, including the University of Colorado-Boulder and the University of Washington, showed great discrepancies in salaries between departments, some with double the average salary of another department at the same university.
...Caryl Emerson, a member of the Committee of Three and chair of the Slavic languages and literatures department, declined to comment due to her position on the committee. However, she said she didn't feel the humanities were poorly treated in regard to relative earnings.
"After all," she said, "we don't make any money for the University."
In contrast, the professors of the science departments are in high demand, not only in academia but also by large pharmaceutical companies and the biotech industry.
....Similarly, economics and finance professors are sometimes lured away from the business world.
"People in the sciences have other options," art and archaeology department chairperson Patricia Brown said. "For us, the other option is probably a museum."
That's priceless, or damn near it. I wish that this basic level of understanding were more abundant elsewhere in the academy. It is a failure of my discipline that it isn't.