Only 1.7 million have sold in Asia. ( That compares with more than 13 million in the US and another five million in Europe) ... also in the other hand the dreamcast the last time i heard (5 years ago) had sold 2.5-3 million units (i think its more the 4-5 million mark in the end as 10million dreamcast where made and sold in the worldwide).
so yeah the xbox was a huge failure in japan. world wide there where about 20million xboxs sold, about the same as the gamecube, (but the gamecube is a little less i think). just to point out MS lost money for every xbox they sold while nintendo made money for every GC sold... so the xbox success (and ninty failure) are not a big as you think