They assume everyone has several TVs, several Gamecubes, several game discs, several controllers, and several friends. PLUS the space, time, and energy to hook them all up and set up the LAN.
Huh? Signature? What's going on with that signature?
Exactly. But you see, as we've both said, they just want more money. If they somehow were able to make Gamecube online compatible, they wouldn't because in the long run they wouldn't get as much money as they would if you just buy a LAN adapter and more controllers and more GBAs and more cables, etc, etc.