That assumes price is the only selling point. It isn't for me; I like the extra portability of the smaller machine. It goes to places a 13" wouldn't because it fits in the bag more easily.

It's not even just used laptops anymore. I sold computers for four years at Office Depot and saw the rise of Netbooks. It wasn't long after that that low end traditional laptops started hitting the sub $400 price range during sales and clearance and customers had a lot harder time justifying the smaller size and lower specs.

I'd say the 13" laptop won't kill the 10" netbook at least until it fits in the same space.

I carry mine with me much more than I would carry a 13" laptop.