Your first link explicitly says "As of December 2012, Windows XP market share is at 21.1% after having peaked at 76.1% in January 2007", but it doesn't really matter. Windows has lots of customers is the point I was trying to make.
Regards to the CEP, when you install Windows8 CEP is automatically enabled unless you choose to install in "advanced" mode; the CEP is opt-out, not opt-in.
Also, if a user opts out of CEP, they are explicitly telling Microsoft to ignore their data. Microsoft shouldn't take their experience of Windows into account because the user instructed them not to.