It’s no secret that the major studios are fixated on their summer movies. By my count, some 27 sequels or prequels will be rolled out this year — about one every other weekend.

The focus on summer is so intense that the release schedule for the rest of the year is starting to look anemic. Box office is down more than 20% thus far in 2011, and it’s not hard to figure out the reason: The movies suck.

There are early signs that at least a few studio executives are responding to this issue. A case in point: 20th Century-Fox.

The year 2010 was not a distinguished year for Fox. Though the studio ranked up there with Warner Bros. in terms of operating profit (the exclusive billion-dollar club), this was also the year of “Marmaduke” and “Gulliver’s Travels.” Fox films did well in the international market (even “Gulliver’s” might pass $200 million worldwide), but what works in Leningrad wasn’t working in L.A.

Lately, Fox has been signing up a formidable slate of quality directors to steer its upcoming slate. The list includes Ang Lee, Ridley Scott, Cameron Crowe and Darren Aronofsky.

I asked the ever voluble Tom Rothman about this the other day and his response was singularly succinct. “Evolve or die,” said Rothman. “We want profitability but we also want originality.”

The upshot is that Fox intends to make more non-sequel films this year, as well as some sequels that have a more original bent. The next “Wolverine” franchise film will emanate from Aronofsky, who made “Black Swan” for Fox Searchlight last year. Ridley Scott’s “Prometheus” started as an “Alien” prequel, but is now emerging as a sci-fi original. “X-Men: First Class,” in the same vein, has been given over to Matthew Vaughn, the idiosyncratic Brit who came up with “Kick-Ass” last year. (“First Class” is set during the Cuban missile crisis.)

Also at work on Fox pictures are David Frankel, who did “The Devil Wears Prada,” and Alexander Payne, who directed “Sideways,” both for the studio.

The Rothman-Jim Gianopulos team insists it wants to make some good movies, but it also wants box office. When “Black Swan” and the “Chronicles of Narnia” sequel recently poked through the $100 million mark in U.S. grosses, they were the first Fox films to do so in a year. “Black Swan” was a low-budget sleeper that kept losing its financing until the week before principal photography. It could end up grossing $250 million worldwide.

The ability of movies like “Black Swan,” “The King’s Speech” or “True Grit” to out-muscle big-budget tentpoles has been confounding many Hollywood executives. This is especially true for Rothman, whose roots were in indie production, having set up Fox Searchlight some 15 years ago.

In addition to presiding over Fox’s four filmmaking divisions with Gianopulos, Rothman also delivers weekly essays on the Fox Movie Channel in which he analyzes some of the great movies of the past. These are usually erudite, most recently holding forth on “How Green Was My Valley” and “All That Jazz.”

To be sure, Rothman’s TV analyses make him something of an anomaly. As one filmmaker puts it, “If he knows the secrets to the great movies of the past, why does Fox make ‘Marmaduke’ and ‘Chipmunks’ sequels?” Rothman and Gianopulos would argue they have a business to run and the experience to run it.

They also have one mega-resource: the “Avatar” franchise. Jim Cameron will shoot a second “Avatar” movie soon, and the Fox executives know he will keep shooting it until he gets it right. And that gives them at once a shudder and a keen sense of security.