If you are thinking about this strictly in the old computer that can do everything paradigm, sure. But in just the past few years, we have used new OS's in our house on a PC, Mac, Tivo, Wii, iPod, iPhone, other phones, car stereo, etc. You get the point. A new paradigm changing netbook-specifically-design OS could get people to try it without even thinking about it.
I got your points.
BUT, you missed the most important point.
Netbook IS a traditional computer, there is nothing make it different than a normal computer, other than light weight and smaller size. it still has 1024x600+ res, it has 1G+ memory, it has 100GB+ HDD, it has powerful enough graphic card to run aero on windows 7.
When users can use a full featured OS like winXP or win7. tell me why they would want to settle on an OS than can only do limited things, and slower (I sure hope google can surprise me on these two fronts)?