Let's compare:
Rare under Nintendo (N64/GCN titles only) (1998-2002) Killer Instinct Gold
Blast Corps
GoldenEye 007
Diddy Kong Racing
Banjo-Kazooie
Jet Force Gemini
Donkey Kong 64
Perfect Dark
Mickey's Speedway USA
Banjo-Tooie
Conker's Bad Fur Day
Star Fox Adventures
Not to mention countless others on the GB* systems
Rare under Microsoft (2002-2005) Grabbed by the Ghoulies
Conker: Live & Reloaded
Let's take a quick count here. Rare release 12 games for Nintendo over 5 years. They've only released 2 in 4 years for Microsoft. Rare has done more development for the GBA portables SINCE they stopped development for the Nintendo console line than they have the XBox (6 games for the GBA versus 2 for the XBox). Out of the games produced, at least eight of twelve are considered pretty well known. Only one of two on the XBox, and that one is at least 50% a direct port.
I could go further on why I really don't care about Rare's stuff these days, but I think it'd be overkill.
Zelda: The Grand Adventures | Triforce MUCK ザ行方不明リンク 悪いユウモアの賢人