To be fair the OP has a point (although Fthr Ted Crilly nails why IMO). Results here will be a bit skewed the average reader of the register doesn't mind poking around their PC, the average home user or even office worker well that may be different.
Windows is entrenched and will be hard to shift, and the average user starting a Linux PC has to relearn some things just to use it, some people will just not do that, or want to, it's a strange new world to learn. You can get frustrated at this attitude, but it's not going to change anytime soon in large numbers.
However with also the average user only doing a few things on a PC, like a bit of word processing, email, web browsing and such (which is probably one of the reasons tablets are taking over), something like the remix OS* (but non spying), a linux build with a dead simple interface (like android I feel people learnt that because they had to to use smartphone, and lets be honest there's lots there people do not know about) a easy to reach app store, and some basic halfway decent word processor etc, could be a killer install for the average home user buying a PC.