The 2 year claim is hollow. Alberto's quotes were right...but they were all sequels. The first Assassin's Creed, for instance, had a longer and more troubled development cycle, because they had to get the engine and tools ships in order.
I can tell you from personal experience that a large chunk of development on new IP (or first take projects) is swallowed by the early engine/tools/core gameplay work. On sequels, you have most of that ready to go, so your two years is better spent on content, new features, fixed features, etc.
I think the line is being blurred now in that 3DS and PSP2 will require more development time than projects past, but it really is all dependent on the project. Echochrome is obviously going to be built much faster than Uncharted, but Uncharted PSP2 is also going to be built much faster than Uncharted 1 since it has existing tools, assets, and code to work from.