I would agree that they should wait another year or two before releasing or even announcing and revealing the next generation console, but not from the money perspective. The problem with electronics today is like someone above me said, they get outdated very easily and very quickly. You can release a console with the very latest in processor and graphic technologies and within a year they could replace it with a newly designed component that would make it even better.
For me, the next generation console needs to be something ground breaking in the video game world. It's pretty obvious that components like the graphics and such would be greatly updated to allow for much better but also more realistic imagery. If you look at PC and games like crysis or if anyone has seen previews of the new cry3 engine, the games today look almost like a realistic virtual world, and this is where console designers need to step it up so they can bring those same elements into the next gen. xbox, playstation or w/e new console could be made. Whether they were to come out with a new console this year or not, people would still buy them and companies like microsoft would still make a large profit from it, but they need to ensure they make everything right and make it up to our expectations as their customer base