I could see windows going that way they are already pushing towards one kernel, UI, and API for phone, tablet desktop. At some point phones will be good enough to run a full blown OS and they might just have one build and just like windows does now it will realize you are on a bigger screen and adjust.
The problem I have with these mobile only fanboys is their solution always involves buying more stuff and hooking it up to fix a clear limitation in the platform. Don't like the security or size of storage? Carry around an external drive that is encrypted. Need a keyboard? Oh carry one of those too. Etc. Before you know it you are walking around with a suitcase of components and cables to connect them all together. Desktops are just too powerful and cheap to not have one. It is like you living without a freezer. Sure you can go to the store every day and buy just what you need that day but the convienence of not having too is worth the cost. It is a pretty large cost if every time you move around you have to detach things, put them away, and reattach all the cables (or dock etc). Even if it is only a few minutes a day you know what? I'll pay 500-1000 for a faster device and saving a few minutes a day for a few years and suspect most businesses will too.