While I think that functionality will continue to converge, and smartphones are pretty close to being there already, I don't think that form factors will. Notebooks aren't as cheap or powerful as desktop workstations, but are more portable. Netbooks extend portability and potentially battery life with bulky extended batteries but aren't small enough to be carried around without a bag. Smartphones offer excellent battery life and connectivity, can be carried in a pocket or clipped to your belt, but the screen size and keyboard can make it difficult to work for long periods of time. There's not much redundancy there. I think most people will continue to have multiple devices and each of those will evolve on their own.