Quote: "There's really no reason for a casual user to be using Windows, everything they do can be done perfectly well in either OS X or Linux."
Honestly, the main reason is that windows is easier to use. You never have to hit a DOS terminal to install software or adjust settings. In addition to this, (and I just know this is going to be really unpopular) Windows software is higher quality. I love the idea of LibreOffice but the fact is Microsoft Word produces nicer looking documents faster and easier. I only moved to Microsoft Office last year when they offered their subscription model because trying to publish from LibreOffice to XHTML and then ePub was unnecessary complicated.
Now this doesn't apply to Mac OS of course which has MS Windows (and please don't talk to me about wine, if you have to install and use wine to run MS Office then it's already too complicated for Joe Average user). But the barrier to Mac OS is the price of the hardware. I can pick up a Windows Netbook able to edit documents and browse the web for less than £175 new, and under £100 used. A Mac Mini with a reasonable spec is still £300 used and over £400 new, plus you have to get a keyboard, mouse and monitor adding another £150 to the process. Or you can get a neat little laptop with better specifications for around £350.
You might hate microsoft for X reason, but the fact is it has the biggest range of high quality software out there
In addition to this Linux doesn't have the support systems in place that allows a customer to phone up and solve problems. The Linux community is too fragmented, there's too many distributions with too many support companies around. If you buy an MS or Apple OS you know where to go for help.
I have to admit also when I've needed support from Microsoft it has been there. The same has not been true for apple unless you want to pack up and go into one of their stores. That's a very nice PR gig, but the reality is they have been very stingy with support in the past.
Now in more recent years Microsoft has taken a lot of heat, the biggest thing is that a new form factor device (the tablet) has appeared that is fantastic for consumers of content who don't produce much. Tablets are fine for someone who wants to write the occasional e-mail, make a shopping list or look up the TV listings. As the Nexus 7 pushed the market down into the sub-£200 price range. That combined with super cheap Under £1 apps has made it very attractive.
It's only natural that Microsoft want to capture this market (which frankly was their market no so long ago, tablets existed long before the iPad). Windows 8 for tablets makes absolutely perfect sense, I've used Windows 8 in that form factor and it really is fantastic to use. But like most people here I am a content creator. To create content you don't need the limited range of Metro apps out there, you need Adobe Creative Suite, App Game Kit, Microsoft Office, GIMP or Photoshop. These devices use the old Windows Desktop interface which isn't finger friendly and makes no sense on platforms like Microsoft Surface.
However Windows 8 as a general iPad alternative consumer device is fine. It's easy to use, and really only lacks because it's store doesn't have any decent apps.
So Microsoft are largely abandoning their Creative Professionals in hopes of pandering to the general consumer market (which it has held firmly up until this point). But I should remind people that the same Creative Professionals have been abandoned by Apple as well. Updates to their creative software packages have been dumbed down in recent years. You only have to look at iMovie to recognise this.
The other name of the game now, is to make customers buy into a single platform. Apple was the first company to really make this sucessful, after all if you have an Apple i device then you're going to have a ton of software from the apple store and videos from itunes and music from itunes. This means customers are more likely to carry on upgrading the Apple line as they slowly refuse to update iOS devices with the latest iOS (iPad 1 is already 2 generations behind at this point). The same is true for Android, devices like the Kindle lock you into the amazon system, and most android devices default to the Google Playstore even if you do have other options for Android. The more you invest in Android/ Apple the more likely you are to continue with that product line. I know for one that I don't like buying the same software twice on both Android and iOS platforms.
So Microsoft want to do the same thing, they want to build up a family of devices (again much like apple have with Mac, iOS and apple TV). To do this they are cultivating their two most popular platforms. XBOX and Windows, and then trying to draw users into that family. Of course this isn't entirely new from Microsoft they have made such half hearted attempts over the years with Windows Media Center and XBOX it's just that no one gave a damn. They also want to expand their media influence by producing TV shows based on their own popular products. In the short term it means angry Microsoft customers, but if they have the balls to actually do a proper job with it then there might be a loyal consumer base in their future.
Either way, love it or hate it, there's plenty of options with Windows. Users aren't being forced to upgrade from XP just yet, merely encouraged.