MICHAEL BARONE: Colleges and universities threatened by COVID-19.

American higher education has been in serious trouble for the past two decades. Yes, it’s true that American universities science and technology departments lead the world, and the (increasingly unscientific) social sciences and (often inhumane) humanities departments can still boast some brilliant scholars. But at some point, too much of a good thing stops being a good thing. People have observed for years that college graduates make more money over their lifetimes than non-college graduates. But it doesn’t follow that people not headed to college will make more money if they go there.

A dismaying number of American freshman college students never end up graduating — not after four or six or 20 years. And an even more dismaying number of non-graduates and graduates end up with daunting amounts of college loan debt, nondischargeable in bankruptcy, which reduces or prevents significant wealth accumulation. Americans today have more college debt than credit card debt.

And for what? In his new book, The Breakdown of Higher Education, John M. Ellis, an emeritus professor at the notoriously left-wing University of California at Santa Cruz, cites multiple studies showing that half of graduates make no intellectual gains — “no statistically significant gains in critical thinking, complex reasoning or writing skills,” as one study puts it. As the American Council of Trustees and Alumni surveys have shown, many schools don’t teach the basics of American history or government. College degrees are not so much evidence of learning as of plodding persistence.

And a willingness to put up with left-wing agitprop, force-fed by “tenured radicals,” in Roger Kimball’s phrase, in traditional academic disciplines as well as grievance studies departments. American universities keep grinding out more Ph.D.s (and more theses no one may ever read) than they have tenure-track teaching jobs, so that an increasing number accept hourly wages as adjuncts and look forward increases in the minimum wage.

Meanwhile, administrators now outnumber teachers at American colleges and universities. Many spend their time in meetings and conferences promoting “equity, inclusivity, and diversity.” Some spend time enforcing speech codes prohibiting free expression that colleges and universities at one time fostered. Others are occupied in regulating adult students’ social behavior, conducting kangaroo courts in which those accused of sexual harassment or assault are denied any presumption of innocence, the ability to call witnesses, or knowledge of any charges.

The notion that adults, who are eligible to vote and serve in the military, need such guidance is rooted in the Latin phrase in loco parentis, the notion that students at residential colleges need something like parental supervision — even if that supervision is irksome and increasingly expensive.

The fact is that the residential college, the model of American higher education since its 17th century foundations, is the exception rather than the rule in most of the world. University students live typically in parental homes or with roommates in cheap nearby apartments. That’s true of most undergraduates in Britain, where Cambridge and Oxford and their beautiful quads were the models for Harvard and William & Mary.

The Higher Education Bubble was kept inflated in no small part by inertia. Now we’re seeing what’s likely to be a transformative change in attitudes.