I think you're still stuck with the notion that competition between consoles is what makes consoles good, when in reality it's the software competition that differentiates them (and as long as there is more than one company making software, this will always happen). The hardware is rather moot in all this -- the difference between Xbox360 and PS3 on a platform level really doesn't matter and is arguably negligable, as the only thing that really differentiates them is the content they provide... and if we could consolidate the platform and provide all the content right there, we'd be set. After 5+ years a new console (similar to how DVD was decided to be the successor of VHS), and we'd all be happy again -- of course my plan doesn't really work until, as I've said a few times now, content creation is the limitation rather than hardware.
I know you were responding to Sis in this post, but I'm trying to explain a way that a single console (monopoly, if you want to call it that) would be far beneficial -- exactly the same way having 1 next gen disc format is beneficial to the consumer. Each generation interval a new consortium would be formed (could even involve several different companies than the previous generation) and they'd get publishers to join the consortium and hopefully the entire industry would agrees on things (like what happened with DVD -- in the end it was pretty much well agreed upon) and we end up with a new console/platform/format to play our trusty games on.
The natural progression of the market seems to want a single platform per generation, and we're here trying to fight against it (at least mainly Sony, MS, and Nintendo are).