I think EBA came out before the big boom of the ds and music games being popular yet effected sales of the game.
EBA was released in 2005 way before Guitar Hero II in 2006 that started the boom.
EDIT: Also can not blame people downloading to flash cards the R4 didn't come into play until 2006 also
EBA was released in 2005 way before Guitar Hero II in 2006 that started the boom.
EDIT: Also can not blame people downloading to flash cards the R4 didn't come into play until 2006 also