That's conjecture. Having stuff working is not the same as having stuff ready to give to the public. If Bungie have a concrete content plan for the next few years (and they should), then obviously that plan has to have some basis in reality. Footage and other media used in movie trailers may or may not be in the final film. Album previews may be remastered several times over before final release. Things change. In any case, being so sore that content shown in a dev log or a demo isn't in the full game is becoming a joke. Like with Aliens Colonial Marines. The way the game looked in the E3 demo versus the final release was the thing people decided to get caught up on, even though it could have looked phenomenal and it'd still have been a pretty shitty game at best.

Yeah, I'm sure musicians of the world cry salty salty tears that you don't get to listen to the tracks they've made that they think is garbage. You know who knows best what should and shouldn't be in a game? The guys making it.