[citation][nom]dragonsqrrl[/nom]It's not necessarily used in a mobile platform.[/citation]
[citation][nom]__ARMd[/nom]ARM will probably begin cannibalizing x86 laptops in a major way soon.[/citation]
And the OS for tablets and mobile phones is good enough for many users that just want to push and play. Featuring keyboard, mouse and other input types will make these platforms the choice for most users, not the power users but the masses will choose something like that instead (think parents and grandparents). That's why Intel is trying to make Android for x86. That's why Windows 8 will be made with mobility in mind.
The appearance of the OS with mobility like features will not prevent heavy productive work or intensive entertainment from being done.
So, here, aiming for the future, all of them, ARM, Intel, Microsoft, Nvidia, Google. Making people have a familiar interface and stop thinking about the rest if they wish not to think about it. Power tools and power users will always exist. Most users, though, will have a docking station that has wireless everything (including inductive charging), and they put the phone there, 1-2 cores, the OS of the phone will synchronize to the OS of the docking station and the same workspace will go on the other device, even as simple as keyboard and screen, or as complex as HDTV and Kinect. The data would be mostly on the cloud anyway, only the local rendering will need the power, so, the more power, the more details and resolution and framerate, but with all the portability needed. Even streaming of pre-rendered video for high demanding entertainment, on the phone, with an intermediate step of being rendered almost locally, for example in the docking station, and then streamed to the phone. All calculations can't be done remotely because of the delay in response time. The delay is tolerable in a locally rendered environment like WoW, because the appearance is "as if you were here", with environment settings being here already, and movements being predicted somehow and synchronized and fluid enough. If everything is rendered in the cloud and streamed over, the experience would never match.
This is the future as I see it from the data at hand. More power, and more mobility, with the dark cloud looming over us all. Not a fan of the cloud, but recognizing it.