Since the end of the 90's Renaissance, Disney has two problems working against them. The first is their need to have complete ownership, and the second is to make as much money off of it as possible. They're always trying to make the next big franchise, but lack the writing/artistic talent to do it. One of my friends considered doing an internship with Disney (and has the talent to easily obtain it), but decided not to go through with it because under contract, any character you create while employed with Disney is property of Disney. The only reason why 'The Nightmare Before Christmas' is considered a Disney film is because Tim Burton created the characters while he was still employed with the company.

If they were more reasonable with property rights, young writers and artists would be more willing to work for Disney. As they keep wanting every movie to be a big hit and want all their rights, they reap what they sow. I suppose you could say this is the case with all of Hollywood but there's something about Disney that makes it more... intense.