Publishers more than ever are unwilling to fund game development on the big consoles if they game might only shift a million copies. Why on earth would they risk it a completly new hardware platform.
It has taken microsfot, a compnay will massive resources and billions of dollars to hand, long enough to become a serious contender in the console market.
There is very little chance of a new player in the market selling loads of consoles. What is left to do, slightly better graphics? We are already seeing new input devices (Wii) and motion tracking on the xbox and playstaion.