Disney has always made a big deal out of the "Disney Vault"—back in the VHS days, they tried to replicate the scarcity of waiting until a movie was showing in a

Disney has always made a big deal out of the "Disney Vault"—back in the VHS days, they tried to replicate the scarcity of waiting until a movie was showing in a local theater by arbitrarily refusing to sell copies of some of their movies for years at a time. I believe they continued this practice with DVDs and Blu-Rays, though not nearly as widely. This seems likely to be part of the same philosophy.