Different builds of a game (God of War 3 trailer related)

First everybody was very hyped about the latest GOW3 trailer. But after seeing the trailer a lot of people were dissapointed. Than David Jaffe said the trailer was from a very early build and lots of people were reliefed. But other people say "why show this build". People always need to complain.

This is not the first time a very early build was shown of a game.

I remember seeing the first real footage of Motorstorm Pacific drift. It wase a very early build with slow flooting cars and with lack of detail in the enviroment. But a few months later an awesome trailer was shown and Motorstorm Pacific drift looks faster, bigger and more detailed than the first game.

Killzone 2 is also a game which looks better every time new videos or screenshots are released.

I am guessing companies have to show something (early-build, prerendered) to generate a certain level of hype or a game will be forgotten very fast. God of War 3 is still a long way, but Killzone 2 is here next February.
Just look at the latest Indiana Jones game. Nothing was shown lately and the game was soon forgotten or presumed canceled.

you can run damage control all you want the trailer was lack luster