The Video Game Hype Machine
If you recall “Spore“‘s promotional campaign, it was similar — tons of gameplay video, the Creature Creator available months before release, and a huge amount of hype surrounding the game. For Triple-A titles, when it comes to releasing content, the rule is simple: Less isn’t more, more is more — often to a parodic extent.
Contrast this with the approach movie promotion often takes. From “Jaws” to “Cloverfield,” movie promotions often try to avoid showing the monster — often until the theatergoers are in the seats and the lights start to dim. Spoilers are tightly controlled, because the theory goes that if people know who Kaiser Soze is or what happens to Dumbledore, nobody’s going to pay to see the film.
Of course, game makers try very hard to maintain secrecy around game plot spoilers. What gets circulated endlessly is gameplay footage, and plenty of gameplay mechanics - which really works as pre-game-release training as well.
Trailers serve the same purpose with movies, there’s just a lot less non-spoiler material to work with.