As we inch closer and closer to what looks like a near-certain deal between Disney and Fox for the former to acquire the film studio of the latter, most eyes are on the transition of rights regarding Marvel and Star Wars, but there's another name that should really be in the conversation. James Cameron's Avatar is a potentially massive film franchise that Disney already has a vested interest in seeing succeed. It means potentially huge business not just at the movie theater, but also when it comes to merchandise and theme park success.
It's absolutely true that reacquiring the film rights to the X-Men and other Marvel properties will be useful for Marvel. It gives them new ways to expand the MCU which will be exciting for fans, enticing them into the theater. Having said that, while the X-Men movies have always been reasonably successful, Deadpool notwithstanding, they've never been the super-blockbusters that many MCU movies turn out to be. Fox also has some lingering rights to Star Wars from the studio's days distributing the first two trilogies, and while Disney will certainly love to make that money themselves, considering how huge Star Wars is, the added revenue will probably be a drop in the bucket.
Avatar, however, is the highest grossing movie of all-time. With somewhere between two and four more movies on the way, Avatar has the potential to make a run to the top of the all-time box office multiple times over the next few years. Even if the Avatar sequels don't replicate the success of the original, they can still make a fraction of the first film's total and still be huge successes. Alongside Marvel and Star Wars, Avatar could certainly be a third major brand for the studio.
But of course, Disney is a many-headed hydra and the box office is only one place where they can make money. The merchandising potential for Avatar is huge. The films don't need to be the biggest movies ever for those that do love them to spend some serious cash on little plush banshee's and Na'vi Halloween costumes. Disney's retail stores would be full of little blue toys. And, of course, so would their theme park gift shops.
Disney and Avatar already are working together in Disney's theme parks. Pandora - The World of Avatar is the newest addition to Disney's Animal Kingdom in Orlando and by bringing the entire property under the Disney banner, the potential for even more integration become simple. Disney already had Star Tours in their parks before they bought Lucasfilm, and that purchase led to an entire Star Wars land. Avatar already has its own land, so a Fox purchase could mean unthinkable levels of expansion for that brand.
The Avatar sequels were almost certainly going to drive people to Disney World anyway, that was part of the point, but after the acquisition, Disney gets to make money on every end of the transaction. The Fox deal will be important for Marvel and Star Wars, but when it comes to the total revenue that each brand adds to Disney's bottom line, Avatar could be even bigger.