On March 22 the great American composer Stephen Sondheim — creator of “Sweeney Todd,” “Follies,” “A Little Night Music” and other Broadway classics — turned 90.

But where was the kind of adulatory media coverage you might have expected? Missing in action, largely. The New York Times splashed out a glowing tribute, but the rest was mainly silence.

Why? Partly the coronavirus was to blame, swamping column inches in newspapers and dominating coverage on network television. A belated, though star-studded, tribute is scheduled Sunday evening — but it’s being streamed on YouTube rather than broadcast.

Are there deeper reasons why Sondheim’s 90th birthday was less a bang and more a whimper? Has his music become something of a niche preoccupation?

David Walsh, director of opera theater at the University of Minnesota, thinks it probably is.

“When Sondheim’s shows came into vogue, they were designed to appeal primarily to fans of musical theater who wanted something a little sharper and more up-to-date than the Rodgers and Hammerstein classics,” Walsh argues.

But the very sharpness that Sondheim brought to Broadway — the biting political satire of “Assassins,” the black humor of “Sweeney Todd,” the desperation beneath the razzle-dazzle of “Follies” — means that a Sondheim musical is harder work intellectually than a typical Broadway show, and less of a comfortable evening out in the theater.

“You have to listen closely to get his irony in all of its flavors” is how Walsh puts it.

That quality of complexity is, however, precisely what attracts the hard-core Sondheim followers, who greedily lap up the kind of nuance and sophistication that Sondheim at his best delivers.

As an example Walsh cites “A Little Night Music,” the 1973 show based on an iconic movie by Swedish auteur Ingmar Bergman.

Walsh directs mainly operas, but said he found profundities he hadn’t expected in Sondheim’s elegant examination of dysfunctional relationships among the Swedish middle classes. “I would say that the finale to Act I — “A Weekend in the Country” — is as challenging as the Act II finale of Mozart’s ‘Marriage of Figaro.’

“Sondheim’s characters are multidimensional and usually deeply flawed, and therefore deeply human. Overall, I would say that staging Sondheim is as difficult as staging any opera, and harder than many.”

Peter Rothstein agrees. He is artistic director of Theater Latté Da, and in recent years has delighted Twin Cities audiences with a string of exemplary Sondheim productions including “Night Music,” “Sunday in the Park With George,” “Into the Woods” and “Company.”

“There’s a real sophistication in the construction and musical arc of Sondheim’s theater, incorporating themes and countermelodies with an intellectual rigor and technical mastery,” Rothstein says. “His lyrics reflect conversational speech and are immediately comprehensible for a contemporary audience. Not all opera does that.”

The relationship between words and music in Sondheim is at the heart of his artistic achievement. Unusually for Broadway, he insists on writing both, and no major composer since Richard Wagner has so seamlessly and intelligently intertwined the one with the other.

Songs like “Being Alive” (from “Company”) and “I’m Still Here” (“Follies”) perfectly distill the durability of the human spirit. “Finishing the Hat” (“Sunday in the Park”) reflects philosophically on the act of artistic creation.

And who else but Sondheim could write a swinging ditty about cannibalism (“A Little Priest” from “Sweeney Todd”) and make it seem amusing?

Sondheim has a song for virtually every flip and foible of the human situation: He’s the Shakespeare of the music theater, with a gift for wry empathy that most other composers only dream about.

That variety of subject matter — from the intricacies of the American colonial legacy in “Pacific Overtures” to the riffs on modern-day relationships in “Company” — is something that has forcibly struck Rothstein in his journey through the Sondheim canon as director.

“His shows vary so greatly in terms of structure, tone, theme, theatrical devices, and of course narrative. I can’t think of another composer who has tackled a wider spectrum of stories.”

And though a Sondheim show can be intellectually challenging, even confrontational — both “Another National Anthem” and “Something Just Broke” from “Assassins” are cutting indictments of the American dream — he is an entertainer to his fingertips, with a special gift for coining wonderful melodies.

“Send in the Clowns” from “A Little Night Music” is a prime example. Set to a gently lapping waltz rhythm, the song is built on a simple four-note motif, rising innocuously like a children’s nursery rhyme.

In the central section, however, Sondheim tweaks the melody with minor key shadings, as gentle reminiscences turn to anxious realization that the past is truly over, its opportunities for love and meaningful connection gone forever.

A simple pop song? “Send in the Clowns” can sound that way, and has spawned dozens of schlocky, sentimental cover versions.

But there’s bite as well as beauty in it, as there is in so many of Sondheim’s finest moments. He is, as Rothstein puts it, “fiercely intelligent.”

And that, perhaps, is ultimately why Sondheim’s reputation is far from settled as he moves into his 90s.

Marooned between music theater fans who find his shows too knowingly clever, and opera aficionados who sniffily dismiss him for being “Broadway,” and by definition not clever or sophisticated enough — that’s Sondheim’s spot, and only time will tell whether the niche he currently occupies will shift to mainstream adulation.

It unquestionably deserves to. Smart, sassy, profound and empathetic, his music theater pieces — it seems wrong to lump them crudely together as “musicals” — represent one of the great achievements of American music.

Amid the tangled incoherence and instability of 21st-century living, we need their wit, wisdom and humanity more than ever.

Terry Blain is a freelance classical music critic for the Star Tribune. Reach him at artsblain@gmail.com.