What doesn't work on Win8?
Running windows 8 on a 4 year old laptop from pre-release versions through to 8.1 and now on a Mac Air with VMware (got it for the hardware, not the OS and found boot camp annoying) I have to say I've yet to find anything in either business or personal terms that doesn't work. Admittedly there's some aspects I like more or less than others but I've yet to use a client machine in c25 years of being in the IT game that I couldn't say that about.
Win 8 difficult to use without a touch screen? Really not in my experience, I've been into it for some time and simply haven't felt the need to fondle my OS (even on the Air), I don't see the issue.
Metro interface? I've seen some really useful and imaginative uses for it aimed at process workers, if they only need three buttons on a screen to do their job then why give then 250 and a set of menus? If you are a knowledge worker and need all that stuff then it's fine, just switch it to desktop mode by default and move on.
The focus on market share based on a number of people hitting websites is a highly spurious correlation at best as others have mentioned, the nature of the way people use IT is in a permanent state of flux but using pontificating on how we like various flavours of the OS seems a moot point, as has already been said the issue is with delivering the services people want in an easily consumable manner; my mother uses an iPad because it's easy for her to do what she needs (consume content)and she also has a PC for when she needs to create content. as/when the PC gives up the ghost I'll move her to Win 8 or 9 or whatever makes her life easier (and limits the support calls!) but I'd be amazed if she knows what an OS is let alone what one she's using.
It's a tool that does a job, pick the right one and deliver service to people in the way that best suits them, if that's fruit flavoured or wears a suit it really doesn't matter