Hollywood had one of its best summers ever at the domestic box office, but it was a sharply lopsided victory. Studios either thrived or withered, an outcome that reflects the winner-take-all nature of the mass-appeal movie business.

Ticket sales at North American cinemas rose an estimated 10.4 percent, to $4.48 billion, for the period between the first weekend in May and Labor Day, from the same period a year earlier, the analytics firm Rentrak said on Sunday. Hollywood’s summer, which was one week longer this year because of a calendar quirk, has historically accounted for up to 40 percent of annual domestic ticket sales.

But the strong season was overwhelmingly owing to movies supplied by just two of Hollywood’s six major studios. Twelve movies took in more than $100 million in the United States and Canada, and eight of them were from Universal Pictures, a division of Comcast’s NBCUniversal, and Walt Disney Studios. Together, Universal and Disney controlled 60 percent of the market, Rentrak said.

Universal’s “Jurassic World” was the No. 1 draw, taking in nearly $647 million, for a global total of $1.65 billion, and Imax theaters did particularly well.

“Avengers: Age of Ultron,” from Disney’s Marvel division, was second, selling $457.8 million ($1.4 billion worldwide).

Third place went to one of the few original movies to hit big: “Inside Out,” from Disney’s Pixar unit, took in $348.2 million ($706 million worldwide).

But almost every other film studio struggled.

The once rock-solid Warner Bros. found hits in “San Andreas” and “Mad Max: Fury Road” but mostly suffered dud after dud, including “Magic Mike XXL,” “Entourage,” “Hot Pursuit,” “Vacation” and “The Man From U.N.C.L.E.” After a stellar summer last year, 20th Century Fox had a major flop this time around with “Fantastic Four.” Sony Pictures was barely in the game at all.

There are two major lessons from all of this, analysts say, one involving Hollywood as a whole and one concerning specific film companies.

For years, Hollywood has pursued event-style movies intended to play to everyone — old and young, male and female, domestic and foreign. (“Old” is defined by the studios as anyone over the age of 35.) But some of these offerings have grown so colossal that other movies, even very expensive and heavily marketed ones that receive decent reviews, are having a hard time getting noticed.

“We’re not seeing as many doubles and triples, and those movies are the ones that really keep the box office healthy,” said Paul Dergarabedian, a senior analyst at Rentrak. “It was an extremely top-heavy summer.”

Last summer, nine of the top 10 movies in North America collected roughly $200 million or more in ticket sales. This year, only four movies did that: “Jurassic World,” “Age of Ultron,” “Inside Out” and Universal’s animated “Minions.”

“Jurassic World” ranked first or second for five weekends in a row. Universal’s “Straight Outta Compton” was No. 1 for three weekends straight. Because of the continued popularity of those films, some competing movies faced a limited chance to play in the biggest theaters, including those operated by Imax and a screen network known as Premium Large Format, both of which charge more for tickets.

It may only get worse: In the summer of 2017, for instance, Disney has new installments from its “Toy Story,” “Pirates of the Caribbean,” “Guardians of the Galaxy” and “Star Wars” franchises opening back to back. That lineup is expected to leave little room for anything else to bloom.

The summer season that just ended also reflected specific problems at certain suppliers. Warner, for instance, has been struggling through a lingering shaky period resulting from upheaval in 2013, when the studio’s movie chief departed in a broader management overhaul.

“Our business is cyclical, and we had a transitional summer,” Dan Fellman, Warner’s president of domestic distribution, said. “The good news is that Greg Silverman and his team are really lining up a series of movies that look to be huge box office hits,” including “Batman v Superman: Dawn of Justice.” Mr. Silverman is Warner’s president of movie production.

Sony, which as recently as 2013 found major warm-weather hits in “Men in Black 3” and “The Amazing Spider-Man,” had the most difficult summer of all. The studio did not have a single film among the season’s top 25 performers, according to Box Office Mojo, a database. “Pixels,” starring Adam Sandler, was Sony’s biggest draw, taking in roughly $73.3 million in North America.

Sony, which declined to comment for this article, brought in a new movie chief, Thomas E. Rothman, in February. Mr. Rothman, who had been working to revive Sony’s TriStar label, replaced Sony’s longtime movie picker, Amy Pascal, who was edged out because of a shortage of hits and the fallout from last year’s cyberattack on the studio.

The fall promises to be better for Sony, which will release the next James Bond film, “Spectre,” on Nov. 6. Sony also got a bit of box-office help over the weekend. Its religious drama “War Room” took in about $9.4 million from Friday to Sunday, for first place.