Rare's old talent is gone, it's all new developers now.
All they can really rely on are the names that were 'taken' from Nintendo, like Banjo, PD, Conker, KI, and Jet force Gemini.
Once they come out with ideas for new games now, it's more of a 'oh look, little bubba wants to say something'. I mean, Xbox fanboy interest for Kameo and GBtG isn't as high as PD or Banjo (COnker is a remake, so no real surprises), since they are franchises from a Nintendo console. There's more interest cause then they can all go 'oh look! These are SOOOO much better on Xbox than Nintendo.' despite the fact that these games do nothing to 'improve' the mature image MS wants for Xbox/2. Only the fact that they can make passes on us Ninty fanboys is only really why they want the games to be good.