Why are academics so unhappy?

After reading this, I'm not sure if I ever want a teaching job:

Universities attract people who are good at school. Being good at school takes a real enough but very small talent. As the philosopher Robert Nozick once pointed out, all those A's earned through their young lives encourage such people to persist in school: to stick around, get more A's and more degrees, sign on for teaching jobs. When young, the life ahead seems glorious. They imagine themselves inspiring the young, writing important books, living out their days in cultivated leisure.

But something, inevitably, goes awry, something disagreeable turns up in the punch bowl. Usually by the time they turn 40, they discover the students aren't sufficiently appreciative; the books don't get written; the teaching begins to feel repetitive; the collegiality is seldom anywhere near what one hoped for it; there isn't any good use for the leisure. Meanwhile, people who got lots of B's in school seem to be driving around in Mercedes, buying million-dollar apartments, enjoying freedom and prosperity in a manner that strikes the former good students, now professors, as not only unseemly but of a kind a just society surely would never permit.

Now that politics has trumped literature in English departments the situation is even worse. Beset by political correctness, self-imposed diversity, without leadership from above, university teachers, at least on the humanities and social-science sides, knowing the work they produce couldn't be of the least possible interest to anyone but the hacks of the MLA and similar academic organizations, have more reason than ever to be unhappy.