Netflix’s Reed Hastings in early March threw cold water on the effort to contractually mandate diversity in film casting and the hiring of physical production crews, dealing the first blow to the burgeoning effort in Hollywood to address long-standing racial disparities. “We’re not so big on doing everything through agreements,” the Netflix CEO recently told USA Today. “We’re trying to do things creatively.”

Save for a handful of top Hollywood actors and producers, no major studio has publicly backed the adoption of inclusion riders after Frances McDormand cemented the little-known contractual term in the national lexicon. Her short but powerful call for the riders at the close of her March 4 Oscar acceptance speech for best actress drew attention to the work of USC media researcher Stacy Smith and others who have toiled to educate industry leaders on how to accelerate efforts to improve racial and gender inclusiveness in Hollywood.

In the weeks since McDormand’s speech, talent agencies and the guilds have been largely silent on the topic, except for WME, where co-CEO Ari Emanuel issued a company-wide edict declaring that the agency would work to adopt inclusion riders. Though supportive of efforts to improve the representation of marginalized groups, the guilds, including SAG-AFTRA, WGA West, WGA East and the Directors Guild of America, have not rushed to the fore to support the initiative.

A spokeswoman for the DGA said the guild is monitoring developments as the effort evolves, but noted that in the last two contract negotiations between the union and studios, the DGA unsuccessfully pushed for the adoption of the Rooney Rule. The principle, used by the NFL, calls for teams to interview minority candidates for top coaching jobs. Spokespeople for SAG-AFTRA, WGA West and WGA East did not respond to requests for comment.

The lack of commitment is worrisome to advocates like WME partner Phillip Sun, who sits on the board of USC’s Annenberg Inclusion Initiative, the think tank Smith founded. Sun argues that even though the language is still evolving, inclusion riders should be part of the strategies used to improve diversity in the industry. “My personal concern is people not giving it a chance to get on its feet,” said Sun, whose clients include Michael B. Jordan, who recently told his Instagram followers he and his production company would adopt inclusion riders in future contracts. “If it’s not given a shot to breathe,” Sun said, “that can hurt it. It’s giving us time to get things to a point that we can go out there and actually fight that fight.”

Jordan, Matt Damon, Ben Affleck, Brie Larson and Paul Feig are among the few Hollywood A-listers and producers to announce in recent weeks that they would adopt or demand inclusion riders involving themselves or their production companies.

Studios’ appetite for adopting such riders on films has varied from interested to noncommittal. A Fox insider said the studio is “actively engaged” with the issue and “exploring a number of options.” At Warner Bros., broad discussion is under way, but talks are preliminary, a source said. Disney, Sony and Universal declined to address the matter, while Paramount did not respond to a request for comment.

“The studios are the ones that need to step up,” said Sun. “Let’s have these conversations and figure out how to get things to where everyone is comfortable. Even though it’s not a fully realized document, the principles are there.”Alana Mayo, head of production at Jordan’s Outlier Society, said the concept found immediate support with the actor, who has become a superstar with the success of films like “Black Panther” and “Creed.” Mayo also sits on the board of the Annenberg Inclusion Initiative.

“Our plan was to be the first to go out and publicly support the efforts of people that had come before us and to lend Michael’s voice, which right now is really loud and significant,” said Mayo. Outlier Society will work to incorporate inclusion riders in its productions, including the recently announced World War II action-drama “The Liberators,” which has found a home at Warner Bros, she said.

Mayo, a former studio creative executive, said she’s concerned that any resistance or lack of support might doom the effort. “I’ve had so many conversations,” she said, “where something that feels completely achievable to me was shot down or dismissed or flagrantly disagreed with for no other reason than it went against the status quo.”

USC’s Smith, who minted the idea in 2014, said she and a team of people, including employment-law attorney Kalpana Kotagal, have worked to make sure the language is flexible enough to address the concerns of all the parties involved in a contract negotiation. Smith consulted with Kotagal and other attorneys to ensure the rider stands up to legal scrutiny.

Smith and her team have released template language that she says allow for a number of customizing options. She said McDormand’s support and, specifically, WME’s adoption have been catalysts in the effort.

“That’s a huge step forward,” she said. At the same time, she’s hopeful that there will be improvements that can assuage concerns over the feasibility of the rider. “The goal is for folks to come to the table and say our performance in the past has been problematic,” Smith said. “Whether it’s the studios, the guilds, production companies — anyone involved in the supply chain in producing, distributing and exhibiting content — we want them on our team to help facilitate change, whether it’s the inclusion rider or other solutions. What needs to happen is the standardization of hiring practices across the industry, and those are conversations that should be taking place across all the different constituents.”