I think, actually, this will start to become their strategy. Using cards from the previous generation to fill the lower and mid-range of the new generation. In a time where profits are down, this isn't a bad idea, and I actually don't know why the video card manufacturers haven't started doing it sooner.
It saves on the costs to have to tape out a new core just to get something that is almost identical to something that already exists.
The renaming is a by-product, and really done to eliminate confusion by creating a unified naming scheme. Granted, I think their renames are kind of shitty. Like renaming a 8800GT to 9800GT, when they are identical. I would have preferred 9700GT perhaps, or 9600GTX maybe. But then again, I would have done the entire naming scheme differently starting with the original release of G92. I think nVidia is still trying to figure out how to handle the new strategy properly in terms of naming, I can't say they've done it right so far for the most part but they've done it right a few time, but I think a lot of poeple are too quick to jump on them and cry foul when it isn't necessary.