Wiow, this is even more popular than I thought it'd be.
In 2004, a new CEO came to disney. One of the first things he did was shut down the animation department; after Brother Bear, all animated movies from Disney would be CG. In 2006, it was decided to create one last movie: Princess and Frog. After this, the animation will be permanently shut down.
Cell animation takes longer than computer animation; Bambi took six years, but Dinosaur took only one. The Lion King took twelve, but Chicken Little took two. It's less laborious, less expensive, and it's starting to appeal to audiences better than regular animation.