That's not the same concept Destiny creates placeholders on disk for them to access so they can texture, tweak, test, and add content to the DLC the areas may be there but the missions, enemies placement, actions, resource/chest placement, and so on are not coded in or finished yet. They also have other things to code such as the vendors, the new way we level up exotics, the new guns, armor, they've got to (somewhat) test the new exotics they've also gotta add whatever amount of cinematics we will get