To the growing catalog of damage caused by the decades-long run-up in the cost of higher education, we may have to add another casualty. On top of the harm high tuition and other charges are inflicting on young people, and the way their struggles are holding back today’s economy, we must add the worry that tomorrow’s economy will suffer, too.

Ever-escalating tuitions, especially in the past dozen years, have produced an explosion of associated debt, as students and their families resorted to borrowing to cover college prices...