Nobody owes anybody anything. These "promises" that game developers and game publishers make are not promises. They're advertising. More hype. Just because a game is announced, and hyped up, does not mean that the developers have suddenly entered into a contract with the general public stating that they have to come through with a game. Sure, Bungie "sold out," but they are a business first. You can't produce games like Myth forever without a solid financial backing. People who create games "by gamers, for gamers" are just selling you something else. It's always about money first, pleasing the "fans" second.
So don't criticize a game company just because they reneg on an announcement. All decisions are financial. Don't forget: developing games is their job.