Why are the producers always so secretive?

Why do they always retain information like keepin their gold in a multi-locked safe?

We get bits of information once in a century. And we wait so loooooong for one single game! Why's that so?

And then it all floods our minds near the game release. Is this actually good to them? Or us?

Basically there are three main reasons why companies do this.

1) Outwit the Competition
So other companies don't steal thier ideas and then implement them in a rushed and unsatisfying game? SquareEnix takes a long time producing it's Final Fantasy games. That's a huge void in time for someone else to steal the spotlight.

2) Build the Hype
From a marketing persperctive, it's not wise to reveal all the eggs in the basket because by the time the game is actually released the hype has died down. People jump up and down at every bit of new facts and footage, but eventually that effect wears off and the general masses move on.

3) They don't know
Yeah, you see... most games in the end aren't always what was originally done on the concept board. As production moves along, things change. For example, if you ever looked at the early trailers and concept art for Okami, they look quite different from the end product. Or how about Halo: Combat Evolved? The game was originally planned as a real-time srategy game but now as we all know, it became a first-person shooter. I could also go on about how Devil May Cry was originally conceived as a Resident Evil game but I think we all get the idea. The bottom line is that companies don't want to release information that might be proven false later on or state features that won't be implemented. Even characters and plot can change throughout production.
RaiKageRyu

stated perfectly...I'd just be repeating him with different examples...