The scholar A.C. Bradley rendered a magisterial judgment in 1904: “King Lear” is Shakespeare’s least popular play—but also his greatest.

I’ve taught Shakespeare to college students for many years, and I can attest that “Lear” is both difficult to like and a profound work of genius. But unlike Bradley, who attributes the problem to technical issues of performance—he called the play “too huge for the stage”—I think its unpopularity is a function of demographics. Viewers and readers can fully grasp it only once they’ve passed...