I think the author is missing a point here: Macbook Air is a full-blown computer (I run several VMs on mine), while Surface is a freaking tablet.

I am ok with 'wasted' space on a computer, because first, I expect OS to have a substantial footprint, and second - I can see, touch, and actually 'consume' the OS files.

I am not ok with wasted space on a tablet, because to me it is a glorified book reader/mp3 player; I expect to use all the available space for storage.

Wait, you are saying Surface is actually a computer (although a shitty one), not a tablet? Well, then MSFT completely failed to communicate this message. Which is pretty regular problem for MSFT.