I suspect they value the offering higher if it's in limited supply. Disney do this with the Disney Vault[1]. Each Disney film is available for purchase for a

I suspect they value the offering higher if it's in limited supply. Disney do this with the Disney Vault[1]. Each Disney film is available for purchase for a limited time, after which it is put "in the vault" and not made available in stores for several years until it is once again released. However, Disney may be the exception here. [1] https://en.wikipedia.org/wiki/Disney_Vault https://en.wikipedia.org/wiki/Disney_Vault