Not that I'm entirely sure how wanting to expand your customer base when your core base has all already bought the game is displaying a lack of confidence.
I'm not really sure that there's many people who can be considered part of a core base if they haven't bought the product almost two years after release (i.e. when G&K was released).
This is neatly circular. The core base has all bought the game. And if someone hasn't? Well, they can't be considered part of the core base!