It's more likely because of Pixar's longstanding practice of keeping its core technologies openly available (Blender is rife with technologies originally developed by Pixar gurus, not the least of which is RenderMan). Disney may be a huge company but Pixar is the only part of it that has ever won an Academy Awards (it has about ten as I remember) except for a single award for Beauty and the Beast. A Pixar guru also runs both Pixar and the entire Disney Animation Studio. Jobs never had a reputation of being generous with patents. It's also just a smart move in general, people are tired of application-restricted file formats in this field.