Honestly MS and Sony will probably copy Nintendo next time and just soup up their existing chipsets for their next machines.
I think even on their side of the fence the appetite to keep losing money on hardware to the point where you're bleeding billions before you even have one profitable quarter has likely substantially waned. Especailly now that they both probably realize as a company they should've been paying attention to the iPod/iPhone rather than thinking video game consoles were the holy grail of electronics and PCs merging together.
While Sony and Microsoft were having a dick waving contest over who would be the next big content company via their game consoles, Apple quietly just took half the entire media market uncontested (music provider via iTunes) and is far ahead in the video sweepstakes as well. And on top of that, Nintendo came out of nowhere and smacked them both down to second and third place.
Beyond that, really what's the point of having a chipset when it's costs a developer a small fortune to make games on it? We're close to that point now, if you get to 10x-20x more power than the 360 or PS3 ... you're getting to a point where like maybe 6 or 7 studios even bother to use all that horsepower.
