Boomers presented school as an investment in ourselves, worth financing with debt because it would pay off in higher earnings later. To hear them tell it, education is the only sure investment in history. That’s now proving preposterous. Well-rehearsed evidence that college graduates earn more than high-school graduates on average conceals substantial variations and significant overlap in earnings between the two groups. By one count, the lowest-earning quartile of college grads earn roughly the same as the top quartile of high-school-only workers, but with more student debt to show for it. A severe student-debt crisis has also developed among young adults who reached for college but found it beyond their grasp, racking up debt with no degree to show for it.