[twiceaday]

That's the point. A laptop with a detachable screen implies a full OS with the ability to run in mobile mode. A dockable tablet implies only a mobile OS. The former can be your only pc while the latter is purely supplemental.

[geon]

There is absolutely no reason why a dockable mobile device would not deliver a full desktop experience.

Have you seen the Android/Ubuntu demo? They ran Ubuntu on a cellphone in a dock. Very impressive.

[Mythbusters]

Windows 8 has a similar experience built in whith the advantage that you have a full OS with you at all times if you need it.