If you know your animation history pretty well, you know that even the biggest studios can have false starts. A major studio can announce the development of a new animated film, only for that movie to never see the light of day, for one reason or another. Pixar, for example, has axed its own titles for being too similar to those of competing studios, like the time it removed "Newt," a film about procreating newts, from its schedule over concerns it was too similar to Blue Sky Studios' "Rio," as one example. Sometimes, though, it's as simple as a studio's executive team shifting, like when Netflix's planned adaptation of the "Redwall" fantasy-adventure book series was sent into development hell because of the studio's changing priorities.

Finally, in select cases, there's an even simpler excuse: If one movie doesn't do well at the box office, any potential sequel goes the way of the dodo.