Indeed, nvidia are definitely late to the game this time, though for a multitude of reasons it would seem. Bad timing is what it comes down to. I don't think ATI are home free yet though. Supply has been scarce, and prices high. Plus, no game recently released has really pushed DX11 or general performance to a level where upgrading from the last set of cards is really worthwhile. In my opinion of course.
If the GF100 doesn't come out the factory with performance to immediately superceed ATI, I believe that in the months following, driver updates are really going to make the difference. It's amazing how much the performance of the G80 and G92 chips has been optimised over the last few years, and this shows with a lot of people still using 8800GT's for example. This hasn't been the case with ATI, and they still have issues plaguing a lot of the new 5xxx series that remain unresolved quite a while after first being discovered. Nvidia seem to have been quicker at sorting these things out and boosting performance.
Things may well change, but don't be surprised if a lot of people are still holding out for the GF100.