There will always be spare change

“There will always be change,” wrote Thomas Friedman in his 2012 column “Average Is Over.”“But the one thing we know for sure is that with each advance in globalization and the I.T. revolution, the best jobs will require workers to have more and better education to make themselves above average.”

Economics professor and blogger Tyler Cowen borrowed Friedman’s title for his most recent book, Average Is Over: Powering America Beyond the Age of the Great Stagnation, but his emphasis, in surveying...