I think people are underestimating Microsofts first party development resources.
Lionhead: Has two teams, it is quite probable that one team just finished Fable 3 and ported it to PC whilst starting a new game and the second team (prediction) was working on Black and White 3 which became a Kinect game.
Rare: Has three teams. They ought to be as productive as Insomniac if not more so in terms of games released. We just haven't seen the results from their recent expansion yet.
Turn 10: Has two teams, hence we're seeing Forza 4 this year, but what is the other team doing? They said they wanted to work on something entirely different to racing games.
343 Studios is definately working on Halo, but are they also working on something else as well? They are picked to be the next flagship shooter developer and their resources shouldn't be underestimated.
Firebird Studios: WTF are they doing.
Alongside their various 2nd party releases.
Finally don't forget that Microsoft EDD just released WP7. As an ecosystem its probably diverted more of their attention in the short term than Sony diverted for the NPG if you want a comparison. Given the likely success of WP7 now that Nokia is on board they now have a bigger handheld empire than Sony does and they may rival Nintendo one day. They also published dozens?hundreds? of games for that platform so they were hardly in a position to go sniiff out games for the Xbox 360 from various major and up and coming developers.
Tease.
