“Fueled by teacher shortages,” we’re told in a recent article in The74, “Zoom-in-a-Room” is making a comeback.

If this is the case, although it’s better than the alternative—no teacher at all—it’s also a missed opportunity for deeper innovation.

As reporter Linda Jacobson noted in the article, online learning has long been used in schools for subjects they couldn’t otherwise offer. She cited A.P. Calculus and Latin as examples. But even courses we think of as fundamental—physics, for example—have long been glaring areas where schools haven’t had qualified teachers. As I wrote nearly a decade ago, “less than two-thirds of high schools–63%–offer physics. Only about half of high schools offer calculus. Among high schools that serve large percentages of African-American and Latino students, one in four don’t offer Algebra II, and one in three don’t offer chemistry.”

According to Jacobsen, “as districts struggle to fill teaching vacancies, they are increasingly turning to companies like Proximity to teach core subjects.” The practice is one in which the teacher of record delivers whole-class learning virtually, and an in-person monitor—often a substitute teacher—tracks behavior and ensures students do their work.