Disney Shuts Down Order of the Seven
First, it costs money. Disney cites this as a problem given that they don't have any left after John Carter.
Second, it's from a first time director (Michael Gracey), which is always a terrifying prospect when dealing with large sums of money that you don't have.
Third, (and I'm just speculating here, although Disney hasn't actually said this) it turns out that the saturation point for films based on Snow White is only two per year, not three. Films three and up on a certain broad topic in a given year have to go straight to DVD. It's the law.
Fourth, while the idea of another Snow White film at face value seems entirely pointless given the release of Mirror Mirror and Snow White and the Huntsman this year, the film's description is actually far too cool for Disney to ever take a chance on it:
A young woman in 19th century Hong Kong who escapes her wicked stepmother and takes refuge with seven men belonging to an ancient order dedicated to fighting demons and dragons.
I would watch the hell out of that film.