I think its well documented that the Godzilla game for the Gamecube, "Godzilla: Destroy All Monsters Melee", sold rather well. It was off to a slow start, but sales kept coming in for a long time after release, which is rare for video games. It should also be well documented that the Xbox port of that game was a total failure.
From this conclusion, one would expect the Gamecube to get the sequel. Alas, that wasn't the case, as "Godzilla: Save the Earth" was released for every system but the Gamecube. The logic behind this move just wasn't there, online play or not. The game sold poorly on the Xbox, and great on the Gamecube, why shaft the system it sold best on? Oh well, Atari rushed the game out anyway (and I do mean rushed, as features were slashed like the first GCN release to meet a deadline), and was tossing out free copies left and right to try and promote it (I got one beacuse of my site). However, it appears this failed to change anything. I don't have exact sales figures, but I do know the game is more or less tanking. It has already been placed in the $15-20 baragin bins in stores too, less than two months after release.
The question is, will Atari learn from their mistakes, or continue to make them? My guess... the latter, unfortunately. [end rant]