You read that I'm not pasting that. But I found an interesting tidbit in the comments
Enjoy if this is true.They aren't allowing for CPU/GPU/RAM upgrades, they're setting a standard architecture much like the iPhone/iPad model.
In other words they'll get rid of the need for the standard generations we're used to, instead we have a generation that just keeps going through improved hardware releases that are faster and more powerful but based on the same architecture, therefore all games designed for Xbox Infinity 1 will work on Xbox Infinity 2, and vice versa, however they'll look better/perform better on Xbox Infinity 2. Just like on the iPhone/iPad I can get Infinity blade 2, and it'll work on my old iPad 1 released 2 year ago and it'll work on my phone or iPad 2. But for optimal performance or some added features you need the latest hardware revision.
Or of course it could be for just replaceable parts like a PC. But at that point the whole system becomes rather redundant to start with.