Correction: An earlier version of this article misstated conductor Murry Sidlin’s position at Catholic University. His title is professor; he is no longer dean of the school of music. This version has been corrected.

The arts in America are borne on the visions of private citizens. Wolf Trap , America’s only national park for the arts, was the brainchild of Catherine Filene “Kay” Shouse, a wealthy, well-connected Washington widow who had a property she loved and a desire to bring more arts to more people more of the time. On July 1, 1971, her brainchild first drew breath when Julius Rudel led the National Symphony Orchestra with Van Cliburn in Wolf Trap’s opening concert. This year, Wolf Trap is turning 40 years old. ¶ By some lights, Wolf Trap has held its own: With an annual budget of $28 million (not counting the National Park Service’s contribution to the facility’s upkeep), it presents about 99 shows every summer and breaks attendance records every year. And it hasn’t radically changed direction over the years. Now as then, Wolf Trap aims to present a range of art, from musicals to Chinese acrobats to Dolly Parton; now as then, it basically represents middlebrow taste. Terrence Jones, currently in his 16th year as president and chief executive of the Wolf Trap Foundation, describes the Virginia facility as family-oriented, a place where people should feel comfortable. ¶ What’s changed is the definition of “middlebrow.” In the 1970s and 1980s, people were eager to see touring ballet companies and Martha Graham, lighter orchestral concerts and well-known classical stars: Yehudi Menuhin, Jessye Norman, composer Aaron Copland conducting programs of his own works. Today, there’s no longer much of a market for ballet and opera company tours (the Metropolitan Opera and New York City Opera, once frequent Wolf Trap visitors, abandoned their regular national tours years ago). And orchestra concerts are not the draw they once were.

“We used to sell out two nights of Tchaikovsky,” says Jones, referring to the early days when the NSO often offered the same program at Wolf Trap over two or more evenings. “Now we’re not even selling one.” The NSO’s all-Tchaikovsky program July 7 had banks of empty seats.

Since Shouse’s day — she died in 1994 at age 98 — there has been a sea change in the position of the so-called “high arts” in our country’s cultural life. There’s no better testimony to this than the shrinking number of big-name classical music superstars.

Ann McKee, Wolf Trap’s senior vice president for performing arts and education, has been at Wolf Trap for 37 years. “When I started out here,” she says, “two hands full of fingers wouldn’t have been enough to count the number of superstars, conductors, composers and soloists who could fill a house on their name alone. Tell me who they are now. A handful or less.

“Because there are so few marquee names . . . they’re incredibly overexposed in the market. I adore Yo-Yo [Ma] and Itzhak [Perlman] and Josh Bell, but if they’re not performing with us, they’re at the Kennedy Center or WPAS or George Mason. I want a fabulous talent who will sell tickets, but how many tickets can they sell in the same market in a single year?”

It isn’t only Wolf Trap that’s feeling the difference. Other similar summer festivals across the country are encountering the issue: Ravinia in Chicago and the Hollywood Bowl in Los Angeles, both, like Wolf Trap, aspire to present a range of cultural offerings.

“It’s been happening for a while,” says Welz Kauffman, the president of Ravinia, summer home of the Chicago Symphony Orchestra. “In 1985, there were about 40 [big classical music stars]. When I do presentations for my board, I always show them that list of 1985 stars and then [the current] five, and people gasp.” (Kauffman and other industry insiders add the names of Lang Lang and Renee Fleming to the three McKee mentioned.)

For years, Ravinia has been struggling with the fact that audiences for Chicago Symphony Orchestra concerts are shrinking and has been drawing criticism for increasing its pop-music offerings.

Wolf Trap has a freer agenda: Rather than acting as the NSO’s official summer home a la Ravinia, it serves as the orchestra’s regular host.

“Wolf Trap invites us,” says Nigel Boon, the orchestra’s director of artistic planning. Where the Chicago Symphony offers 20 concerts a summer at Ravinia, the NSO has never offered more than a few each summer at Wolf Trap. This year’s series, officially known as “NSO@Wolf Trap,” involves 10 concerts.

And rather than bringing a taste of the NSO’s regular season to a wider public, these concerts deliberately reach out to the tastes of a non-classical audience: “Video Games Live,” “Disney in Concert.” It’s worth noting that some of the crossover projects, such as “Tan Dun: Martial Arts Trilogy” on Aug. 5, are arguably of more artistic interest than a classical chestnut like Tchaikovsky’s “1812 Overture” in its gazillionth iteration.

The programming, created in conjunction with the NSO and Wolf Trap, doesn’t show a lot of faith in classical music’s inherent appeal to a wider audience.

“The way I look at it, [it’s] for people like my parents,” says De Cou, “people who might go to one concert a year or two.”

He adds: “An honest American take on performing is making it open to everybody. . . . I will do anything, put on a chicken suit, if it gets an audience.”

The point is to expose people to the particular joys of live performance, rather than proselytize for future orchestra subscribers. De Cou notes that the informality of the outdoor setting allows the orchestra freedom to try new things, including tweeting program notes for Beethoven’s “Pastoral” Symphony a couple of years ago.

Wolf Trap has not abandoned its commitment to the high arts; it has just shifted it. According to Jones, there are four main “pillars” of Wolf Trap, one of which is the Filene Center, the 7,000-seat amphitheater where the summer performances take place. The other three are the Barns, the intimate 300-seat theater across Route 267 that offers a range of concerts during the regular season; the Wolf Trap Opera, a distinctive little company focused on giving experience to young artists at the beginning of their professional careers (its contribution to the 40th anniversary is a gala concert of successful alumni, including Lawrence Brownlee, Stephanie Blythe and Denyce Graves, on Aug. 24); and an education arm that includes a significant national initiative for early-childhood education, with 15 outposts across the country.

“A good many people got to know Wolf Trap as a performing arts venue,” McKee says, “but there is this massive community across the country who are early-childhood educators who have known about the institute for 30 years . . . and they don’t know that we do performances.”

In Jones’s view, the more popular — and often commercial — acts at the Filene Center every summer have a particular role in Wolf Trap’s ecology.

“The Huey Lewises of the world are helping us create opera; they’re helping us create our education program,” he says. “Without those sellouts of those kinds of shows, we wouldn’t be able to sustain the rest of the mission of the foundation.”

Jones touts the fact that Wolf Trap has commissioned 70 works of art in the 15-plus years of his tenure. Most of these works have been commissions for small dance companies, pieces for various education programs or short chamber works performed at the Barns, but a couple have been noteworthy. The 2004 opera “Volpone” by John Musto and Mark Campbell was successful enough to be revived, recorded, nominated for a Grammy and followed up with the slightly less-successful opera “The Inspector,” which opened in April.

A fan of the so-called high arts can easily look at Wolf Trap’s early years — the Cleveland Orchestra! Martha Graham’s company! — and feel the center has turned from its original mission to present art. But variety and mass-market spectacle have always been a key part of Wolf Trap’s DNA. (One of Shouse’s coups was securing the Edinburgh Military Tattoo, complete with ranks of bagpipes, in what was evidently an eye- and ear-popping salute to the American bicentennial. Shakespeare it wasn’t.) Wolf Trap has never aspired to act as a trailblazer: It simply wants to entertain audiences with things that they will like.

“I don’t know that Wolf Trap has an identity,” says Murry Sidlin, the conductor and professor at the Catholic University’s school of music, who in the 1970s, as a resident conductor of the NSO, conducted many times at Wolf Trap, “other than providing entertainment, whatever that means to whoever uses the word.”

And entertainment, today, means something different, as festival directors everywhere are finding out. “There’s nothing wrong with being all things to all people,” Kauffman says of Ravinia. The statement could apply to Wolf Trap as well, where the so-called high arts are more likely to be found at the Barns, playing to an audience of 300, rather than in the Filene Center.

Wolf Trap, after all, knows its audience.

“For the capital of the free world,” McKee says, “we find our audiences not that adventurous. They want people to tell them that something is safe.”