A child watches a screen promoting a Star Wars toy at a store selling Star Wars merchandise in Los Angeles. (Frederic J. Brown/AFP/Getty Images)

There has never been a time when so much of American entertainment has been controlled by so few.

Disney and Universal have pocketed nearly 90 percent of the U.S. box-office receipts of the year’s top 10 films, a two-studio dominance never before seen in the movie industry. They also own the world’s 12 most visited theme parks and control the most lucrative franchises, including Marvel and “Jurassic Park,” in toys, games and beyond.

And from every corner of Disney’s vast empire, everyone’s raving about “Star Wars: The Force Awakens”: George Stephanopoulos is swinging a lightsaber on ABC’s “Good Morning America,” ESPN is spotlighting the new movie trailer on “Monday Night Football,” and ABC “World News Tonight” anchor David Muir is transitioning from a fatal police shooting to the question: “Do you remember your first ‘Star Wars’ movie?”

In the same way, NBC News breathlessly introduced its segment on its parent company’s “Jurassic World” by saying: “If you think that creating a brand-new dinosaur would be fun . . . well, then you would be right.”

That so much of American leisure time is shaped by two massive conglomerates has some worried about the outsize influence they could have on cultural ideas, cherished stories and childhoods.

Chinese Star Wars fans hold light sabers at they pose for a group photo during a promotional event for the movie "Star Wars: The Force Awakens.” (Mark Schiefelbein/AP)

“What Disney is doing now is having a huge effect on culture, on news, on the way we express ourselves, because of its immense wealth and power,” said John Jewell, a director of Cardiff University’s school of media and cultural studies. “It’s that danger of becoming a monoculture, where everything is Disneyfied. It’s the illusion of choice, because you’ve got five companies owning the same thing. . . . If you’ve got 57 varieties of cornflakes, they’re still cornflakes.”

A media juggernaut milking its franchises through a web of subsidiaries is nothing new. But critics say the two entertainment giants are expanding that promotional machine to an unprecedented scale.

The two companies are virtually unmatched in how many industries they dominate. Comcast, the world’s largest cable company, owns some of the biggest brands in news (NBC, “Meet the Press”), movies (Universal Studios, “The Fast and the Furious”) and sports (with channels that broadcast “Sunday Night Football” and the Olympics).

Disney owns ABC and ESPN, as well as many of the most recognizable names in entertainment, including “Indiana Jones,” Marvel superheroes, Pixar and its own studio, known for films such as “Frozen” and “The Lion King.”

But no premiere has brought Disney’s power into sharper focus quite like the upcoming “The Force Awakens” film, which could not only become the highest-grossing movie in history, but further blur the lines between where the company’s business stops and American culture begins.

In early September, ABC’s “Good Morning America,” the country’s most-watched morning show, staged a global “unboxing” of new “Star Wars” merchandise to promote Force Friday, a retail sales holiday Disney invented. On his late-night show, Jimmy Kimmel revealed four more items while wearing Chewbacca Crocs.

Threading the ad blitz through the news cycle, the football game and traditional kids’ TV helps the movie find a broader audience and gives fellow media properties an advantage over the competition. When “The Force Awakens” unveiled its newest trailer last month, it was cast as an unmissable exclusive, broadcast during the height of prime time on ESPN’s “Monday Night Football.”

Universal, Disney dominate box office

“Do you see the synergy here, people?” said “Good Morning America” anchor Lara Spencer last month, after the show hosted the official poster’s “intergalactic debut.” “We are getting all of these exclusives for you.”

Universal Pictures delivered the same style of exclusive to NBC. The “Today” show was granted an intimate group interview to talk about the death of Paul Walker with the stars of its parent company’s “Furious 7” and, a few months later, blanketed its studio in yellow to promote the “Minions” movie. In another segment, stars Chris Pratt and Bryce Dallas Howard roamed around a “Jurassic World” toy store. The Universal film went on to become the second-biggest blockbuster in U.S. history.

“It’s never happened to this scale before, where they aren’t just advertising through the toys but through serious broadcast programs on current affairs,” said Jewell, the Cardiff University director. “But that’s the real genius of it: It is a news story. It becomes a news story. . . . It just so happens you’re also promoting your own product.”

Spokesmen from both companies defend the dizzying “synergies” as always being noted with public disclaimers that the movie and news businesses are corporate cousins. An ABC News spokesman said “Star Wars: The Force Awakens” is a “global cultural phenomenon” covered by many news outlets, including The Washington Post, and viewers are hungry for whatever information they can get.

“That’s one of the big advantages of being a global media company, the synergy between the sister companies,” said Universal Pictures spokeswoman Teri Everett. “It just makes sense and, I have to say, it works very well here. It feels organic. Divisions have very good relationships with each other.”

Neither Disney nor Universal would detail how it is keeping these lucrative synergies in lockstep — or how it keeps them from going over the line — but they said they would remain as important as ever.

“I’m not going to get into the machinations of it,” Everett said, “but the company makes it a priority.”

The synergy does not stop at news. Disney will break ground on “Star Wars”-themed lands at Disneyland in Anaheim and Disney’s Hollywood Studios in Orlando, one of its biggest expansions of theme parks that have set attendance and profit records for several straight years. And it will take its hype to the seas, next year launching a series of “Star Wars” Caribbean cruises.

“The Force Awakens” will be joined by two climactic sequels, as well as blockbuster side anthology films, planned for box-office releases every year through 2020.

“The seeming everywhere-ness, the ubiquity of these movies, is more powerful or profound in its impact on the audiences if they think it’s more random than strategic,” said Paul Dergarabedian, a senior media analyst with the Rentrak research company. “It lends an air of this collective wanting, to be a part of something that the audience feels is a big deal. They’re thinking, ‘God, this movie is everywhere!’ ”

Critics say this self-perpetuating stranglehold on culture can end up suffocating everything else. When every girl in every movie is a princess or touched by magic, and every boy a swordsman or superhero, that exposure can shape those children’s self-images, their future spending and even the stories they pass on to their kids.

“That’s how Disney has maintained their success, their popularity, over such a long time: because of that generational appeal, that appeal to memories,” said Janet Wasko, a University of Oregon professor and author of books on Disney and the media. “It’s very deliberate. Disney memories are the memories you want to share with your kids, your grandkids. The audience in some ways has to buy into it.”

But, Wasko added, “that this oligopoly is operating and really dominating the entertainment world, that says something for competition — in that there’s not a lot. That has consequences for the kinds of products we get, the certain kind of film that gets emphasized. The emphasis on big films, the whole blockbuster phenomenon, is not going away.”

The media giants are constantly finding new ways to explore the outer limits of their synergy. Procter and Gamble’s CoverGirl has announced it will sell “Dark Side” mascara in tubes printed with “Star Wars” film quotes such as “You will meet your destiny.” Last week, Disney Consumer Products unveiled a new line of Marvel- and “Star Wars”-themed fruits and veggies, including Yoda green seedless grapes.

When you’re a monolith like Disney or Universal, “it’s your sandbox,” Dergarabedian said. “When you own all the toys, you can play with them whenever you want.”