Decades before he took on the chairmanship of the National Endowment for the Arts, Broadway producer Rocco Landesman approached his friend Robert Brustein about doing a musical at Brustein’s artistic home, the American Repertory Theater in Cambridge. Brustein liked the idea, and the show, “Big River: The Adventures of Huckleberry Finn,” opened there in 1984. It would go on to run for more than 1,000 performances on Broadway, win seven Tony Awards, including the coveted best musical, and earn the ART well over $300,000 for having premiered the piece.

Whether or not that show’s high-profile success enticed other nonprofits toward Broadway, as a new report suggests, collaborations between regional theaters and commercial producers have proliferated in the years since then — and Boston’s biggest producing theaters have certainly been a part of that. At the ART, think “The Gershwins’ Porgy and Bess,” “Johnny Baseball,” this December’s revival of “Pippin,” and, potentially, February’s “The Glass Menagerie.” At the Huntington Theater Company, think “Alfred Hitchcock’s The 39 Steps,” “Captors,” “Pal Joey,” and a series of plays by August Wilson.

Slated to be published Monday, the report from the Emerson College-based Center for the Theater Commons chronicles a gathering last November of some of the biggest names in American theater, including Brustein and Landesman, and raises pointed questions about what those partnerships — and a gaze increasingly directed toward Broadway — mean for the mission of nonprofit theaters.

“If there was a recurring theme to the . . . discussion, it was that the nonprofit theater appears to have lost sight of its values and raison d’être,” says the report, titled “In the Intersection: Partnerships in the New Play Sector.” While “commercial partnerships were not perceived to be the cause of this erosion of ideals, necessarily,” it says, there is a concern that the collaborations — which frequently involve so-called enhancement money, paid by the commercial producers to cover production costs at the regional theater — “have the potential to create a legal and moral slippery slope for nonprofits.”

“There’s an uneasiness about the relationship between not-for-profit and commercial theater,” Polly Carl, the director of the Center for the Theater Commons, said in a recent interview. The research center opened at Emerson this year, aiming to shake things up in the American theater, asking questions about its methods and its values.

“There are no purists at the table. I don’t think anybody is saying, ‘Commercial is evil and not-for-profit is good.’ Nobody believes that,” Carl said. In fact, she added, there is value in the two sectors working together. But there is also a sense that the nonprofit theater in recent years “has lost its way in its overemphasis on definitions of success that are very particular to taking shows to New York, not necessarily serving communities.”

As Brustein reminded his two dozen fellow participants in the meeting last year, held at Arena Stage in Washington, D.C., this country’s nonprofit theaters were founded as alternatives to its for-profit theater, with different objectives and ideals.

“We didn’t join together to do the same things to please the largest number, to bring in the greatest amount of money, and the greatest subscribers,” he told them. “[A]s a nonprofit theater, most of us did these things because nobody else would do them! We did Robert Wilson, we did Andrei Serban. . . . Because Broadway wasn’t going to do them! And they needed a voice! They needed an outlet. They needed a stage.”

Avant-garde theater artists aren’t the only ones looking for an outlet. Nowadays, when commercial producers need a stage, they frequently approach nonprofit theaters. Major regional companies like the Huntington and the ART can mount a show for a fraction of the price of a production on Broadway, where nearly everything costs more, and help in the development of the piece, not least by putting it in front of an audience.