(PS: to Pherule: check out LinuxMint, its pretty clean and more understandable then Win8 - somewhat).
Anyways - when you count all computer/tablet/phone devices out there. Microsoft has been reduce to 20% market share in a matter of 5 years (from 90%+) More and more people are using their phones and tablets as THEIR MAIN computer. My GF uses her 4" Android phone as her main computer... even thou she is welcomed to use my iPad or a notebook I have handy.
The only need for Windows with most people is a support system for MS-Office. Games... consoles. Any device out there today can access the web, facebook, email, take photos, etc.
Even today, I'm still using office 2003. I'm building a new i5-3570k system for a client - using Windows7 and his Office2003 disc. I sometimes think "$120 for Office2010 is a good deal for 3 installations" for myself, but I keep finding myself without a real need to get it. I sure as hell won't bother with Office 2013, its ugly as hell and is not much better than Office2010.