The latest Forbes features a conversation between publisher Rich Karlgaard and Jeff Joerres, CEO of Milwaukee-based ManpowerGroup.

It includes the following exchange:

Fifteen percent of parking lot attendants have B.A. degrees. Would more students be better off going to a trade school? Clearly. This trend started in the 1970s—and for the right reasons: The knowledge economy will need knowledge workers. But the knowledge economy was defined too narrowly. It was defined as a service industry. We failed to see that manufacturing would also be part of the knowledge economy. In many ways manufacturing has a bad name. Parents want to send their kid to a college, not a trade school. That the kid might end up waiting tables with his history degree is, weirdly, considered a better result than if the kid had gone to a technical school and become a master plumber. Even though the plumber will earn four times as much as the waiter.

This will not surprise George Leef, chief expositor of the notion that college is oversold.