We are talking about making the distro as lite as possible. Putting the entire games suite takes up another big chunk. I never understood the reasoning behind the "games suite" to begin with. Wouldn't it be better if people chose their own games?
For most Windows users, there are only four games -- Solitaire, Spider Solitaire, Minesweeper, and (for some) the pinball game. When they see all of the games available from the live Ubuntu CD, they are interested in finding out more. As a selling point, seeing the list of games already installed has impact on end users. Showing them all of the games available for free via the package management system just seals the deal.
(Yes, XP has the Internet-enabled games as well. Meh.)