No, I'm suggesting this based upon a few things:
1. Die shrinks are slowing. And as we get smaller, it gets harder and harder to build the processors on the smaller dies. As such, as we move forward we're more likely to see IHV's not increase transistor counts dramatically on their first products for a particular process for reasons of yield.
2. The 80nm shrink should be very closely in-line with when the first DX10 parts should be shipping.
3. We already have the majority of the features that DX10 parts will need, so increases in transistor count on the order of what we have seen in the past are less likely.
In sum, I do expect that the first DX10 parts will be high-end parts targetted to sit at the top end of the scale, with configurations very similar to the parts to be released this coming Spring. That is to say, from ATI I would expect a Xenos-like setup with 48 shader pipelines and 16 texture pipelines, and from nVidia we'll probably get something almost exactly like the upcoming 90nm version of the G70 except with added DX10 features.
So, ATI will save some transistors by getting rid of the vertex pipelines, though both IHV's will have to add some more transistors to support DX10-level functionality. I don't expect to see either IHV really press the 80nm process to larger die sizes until the refresh of these parts.