i think they tried this already with the Moto Atrix and that failed. seems people refuse to combine mobile and desktop.
To be fair, that was a piss poor implementation. Not so much the software or hardware in of itself, but rather, the combination, and performance was crude and slow.
Microsoft has the right idea today, and I think they have a damn good shot at really driving home that advantage once they get their priorities in line. They are kind of putting Windows Phone on the backburner for now, not killing it but not really investing significant developer time on improving it. But they have that phone+dock idea in the works and with the Universal Windows Platform, could make it one hell of a thing. Considering that mobile phones today blow phones like the Atrix out of the water is a big point, but it's also the overall implementation.
Android isn't far behind either, and I firmly believe the reports that Google is working on merging Android and ChromeOS. They have the desktop metaphor in a very alpha state already within the Android N preview, so I think the prediction in this thread that the docked phone setup is going to take off, is rather astute. I could even see myself using such a thing from time to time, but for my usage, it would hardly replace a desktop. But serve as a quick means to get work done that needs a keyboard and mouse but I don't need everything else? Absolutely.
I think long-term, we are also not far away from portable dumb tablets, which use WiDi or a newer wireless display tech to connect to a phone in our pockets. I'd use that too, for sure, and I don't even have a tablet right now. Never really got into tablets, I love the idea but from a practicality standpoint, there are more cons than pros in my eyes. Great for what they can offer, but not much for how I use computing. But give me a bigger screen extension of my phone? Yes please.