You miss the point. If Microsoft want to make a lot of money in the mass market, then they will need to support the current generation of laptops, not the bleeding edge.

I'm not saying that splitting the screen from the laptop is not cool, as I'm no Luddite! I'm merely remarking on the fact that Windows 8 seems to have been designed for the next generation of hardware, but there is no guarantees that this sort of hardware will be adopted by a large proportion of the market any time soon.

It's usable by both. Windows 7 was not. There were many times on my touch screen laptop I wished buttons were better for touch. People act like Windows 8 is only usable on a tablet, when it's not. It will install and work fine on your desktop.