I doubt either the 360 or PS3 will be replaced within the next 3 years. I think the Nintendo's Wii has taught Misco$oft and $ony that content is more important than "cutting edge". Why spend billions developing the most powerful console in the world when most people prefer good games to pretty games? Sure 1080P gaming would be nice, but most people will not be willing to shell out another £300 to £400 to get it.
Hopefully game makers are telling the Wii and Nintendo where to shove it.
The problem is, Nintendo made a killing for THEMSELVES on the hardware, some games are selling well, sure, but lets be honest 98% of the best games being released are on the "real" consoles. I know dozens, and dozens, upon dozens of people with a Wii who never ever play it. ALl those same people have another console and play it all the time.
Dev's don't like the Wii, and game makers aren't making tonnes of cash. MS and Sony may short term and maybe even long term lose money on the hardware, and it may sell less being more expensive, but all the companies that make games for the 360/ps3, make millions a year, they love the consoles, overall those consoles being up to date generate a heck of a lot more total revenue than Nintendo manages to make itself.
If the Wii had "pretty good games" that might be a different issue, if you want to play stupid tennis with your mum when you visit her or jump around like a drunk fool playing golf, fine, but gamers, use a real console.
Theres a point where console gamers see their friends PC games and think WTF, I just played that on my 360, it looks like ass, at which Sony/MS release a new console.
Even easier for them, they went multi cpu, they really don't need much more power except bigger hdd's as standard that are faster, marginal Cpu upgrade, far more powerful gpu.
Wasn't the rumour for a while now that ATi have Nintendo's next project and Sony supposedly want to use Intel for graphics, or maybe ATi, just really they aren't interested in Nvidia who they hate. Everyone seems to hate working with Nvidia, Intel, amd/ati obviously, Sony, MS, all their partners, people that pay Nvidia for their work, hate them, people Nvidia pay stacks of cash to support their hardware, don't mind them. Not the best way to run a company.
The mere fact that Sony are considering an unreleased Larabee over Nvidia should be a clear indication of their relationship.