“The show must go on” is a grand old phrase of show business, but whatever god of theater put it to the test recently in Tempe was pushing things a bit too far. “Hello, Jerry!,” the long‑awaited tribute to Broadway songwriting legend Jerry Herman, presented by ASU’s Herberger School of Music, was to have featured Paige O’Hara, Karen Morrow, Jason Graae, musical director Donald Pippin and Herman himself. But by the time Saturday, Oct. 28, rolled around, Herman and Morrow were absent due to illness, leaving three entertainers to do what had been planned for five.

“Welcome to ‘Hello, Jerry!’ the incredible shrinking musical,” Graae quipped as he opened a mini‑version of what was a small‑scale show to begin with.

And yet, in its very tenacity, not to mention the cheeriness of its songs, “Hello Jerry!” was an example of what the American musical has come to symbolize: Optimism.

That isn’t a very popular trait right now. It hasn’t been a popular trait for a very long time. The last time it was chic to smile and believe things are gonna be great was probably 40‑plus years ago, and truth be told, it doesn’t look as if optimism has much chance of reemerging as a national sensibility any time soon. But musicals are rife with optimism–some would say they are infected with it–and the musical, as any look at the playbills of our local theaters will testify, is as popular as ever.

Jerry Herman’s shows are the epitome of the Broadway keep‑your‑chin‑up attitude. “Hello, Dolly!,” “Mame” and “La Cage aux Folles” are his three best‑known shows, but there are also “Mack and Mabel,” known among Herman connoisseurs and the Broadway‑savvy as his best score; plus such near‑hits as “Dear World” and “The Grand Tour.” Herman grew up around shows with songs by people like Irving Berlin and Cole Porter, and his style reflects that unabashedly. Think of his title tune to “Hello, Dolly!” from 1964 and it’s not too far a musical jump to think of Berlin’s “Alexander’s Ragtime Band” from 1912.

Yet it isn’t only sunshiny songs of that mold that give the musical a reputation for never‑say‑die. Whatever their styles and however tragic their endings, musicals insist on positive messages. The ending of “West Side Story,” with Tony dead on the ground, blooms with the hope of “Somewhere.” The finale of “The Man of La Mancha,” with Cervantes being marched off to prison, assures us that it’s still possible to dream that impossible dream. “A Chorus Line” seems to end in everyday, real‑life cruelty, as half the aspirants to gypsy glory are turned down for the job. Yet, there they all are in the final number, swirling about the stage in top hats and gleaming smiles.

Even newer shows with apparently anti‑optimistic agendas can’t escape. The story of “Sweeney Todd” may be grisly, but in the end, evil is punished and young love triumphs. “Avenue Q” is adult and edgy, but it’s also all about being young and struggling and knowing it’ll all come out OK–optimism re‑imagined. The grinning cynicism of “Urinetown” is only made possible by the undercurrent of optimism assumed beneath its surface.

As it is in the art form, so it happens to be in Jerry Herman’s life. After hitting huge with “Hello, Dolly!” and “Mame” in the 1960s, the last decade when it was possible to write in his style without special permission from the culture, Herman entered a slump period of nearly 20 years. Overt optimism was out, and so were the kinds of songs he was good at writing. Yet he persisted, show after show, until he found a combination that sparked a hit: the warmly sentimental, yet archly humorous story of the French movie, “La Cage aux Folles,” and his old‑fashioned, yet crisply composed songs.

That was 1983, and the last time Herman had a hit show. Shortly after that, he was diagnosed HIV positive. With resolve that even a Broadway show would find hard to muster, Herman called his diagnosis “a miracle,” because through it he could show people “there can be a second chance, that it (AIDS) can be a manageable disease,” as he said in an interview in 1996.

And here he is, ten years later, managing that disease and still writing shows. (The reason for his absence the night of the show was not AIDS, but shingles.) The latest Herman musical, in progress, is called “Miss Spectacular,” and is being designed as a casino show for Las Vegas.

Like Herman, the musical theater survives and occasionally thrives, despite misfortunes and changing styles. It is a form that will not die, and even as the musical seeks to reinvent itself, it persists in reinforcing the eternal virtue of optimism. To judge from the musical’s longevity, that’s not just wide‑eyed silliness. That’s truth‑based, survival‑oriented realism.