"but in practice the few attempts at this have failed, mainly at the hardware level. See the Motorola Atrix, previous Windows Tablet Laptops, etc"
I am typing this response on an ASUS Transformer laptop, which I don't see as a failure at all at the hardware level. The only downside of the ASUS Transformer is that the Android software ecosystem has a long way to go to catch up to the idea of being run on a laptop-like device. This is something Windows 8 should have a big advantage on, which is one of the primary reasons I'm really looking forward to Win8.
I am typing this response on an ASUS Transformer laptop, which I don't see as a failure at all at the hardware level. The only downside of the ASUS Transformer is that the Android software ecosystem has a long way to go to catch up to the idea of being run on a laptop-like device. This is something Windows 8 should have a big advantage on, which is one of the primary reasons I'm really looking forward to Win8.