I hate to be an "I told you so" but I did say that Windows 8 and Windows RT will cause a downfall of Microsoft.
First off, Microsoft stole the business plan of Apple, what works for Apple might not work for Microsoft. The Windows RT Surface tablets got aimed at the Apple iPad market and while the Surface costs less than an iPad, it just isn't as good. Microsoft is now attacking the iPad and dumping RT Surface tablets on the market by cutting their price.
Secondl,y Windows 8 is about the worst OS since Windows Vista or even Windows ME. I doubt Windows 8.1 will be any better. Windows 7 was about the best OS Microsoft could make, but many stuck with Windows XP. Windows 8 tried to go for this AOL 1993 for DOS look with the Modern UI and of course made it harder to use. If someone bought Windows 8 upgrade for their PC and it lacks a touch screen, it is going to be very difficult to use.
Thirdly, Windows 8 Phones are just about horrible and I don't know of anyone who seriously thinks of using one. Even the Blackberry phones outsell Windows 8 Phones. Android is about the best selling for a reason, it runs fast and has fewer crashes than the iPhone and other phone. Android is based on Linux and Java and just works. Apple sells iPhone because they are popular and used as a communications device, Facetime works great if you don't know how to install Skype because it is built into the iPhone. Windows 8 Phones have no 'killer app' like iPhone and Android phones.
Fourthly, Microsoft entered the hardware market and thus upset their OEMs that they now compete with, so now Microsoft has a lot of hardware devices that they cannot sell and have to dump on the market.
Many of us upset at Microsoft switched to Macintosh systems, or just downloaded a Linux ISO and installed Linux to use instead of Windows 8. Linux is quickly becoming the third OS next to Windows and Mac OSX as Valve Software ported the Steam store to it, and keep porting video games to Linux. Gabe Newell himself used to work on Windows for Microsoft and runs Valve and stated that Windows 8 was going to tank and ruin Microsoft, and so far he seems to be correct on that.
I think that we are starting to see the end of Microsoft unless:
Microsoft switches gears and brings back Classic Windows by using the Windows 7 code to make Windows 9 and quits the whole Windows 8 or 8.1 mess. Microsoft stops making Surface tablets and instead partners up with some OEMs to make a better Touch screen tablet device with them so that HP. Dell, Acer, etc can save their companies as well. Microsoft should work with Linux developers to port Ubuntu Touch and other stuff to the Surface Tablets so at least they have some resell value. The Windows 8 Phones are good if you can convert Android 4.2.2 to them to convert them to Android phones as Apple will never let you convert iOS to them partner up with Samsung, LG, and others to make better phones and give them an option to use Windows 8 Phone if they wish.
Make a deal with Barnes and Nobel to sell your Microsoft Press books on their Nook store, and instead of making your own tablets make a deal with B&N to port Windows RT to their Nook tablets. B&N just stopped making their own hardware and licensed it to a third party, you might want to use the same third party to make Surface RT tablets for you if you wish, with an Android option to work as a Nook tablet.
Make a deal with Valve Software over Steam and have an option to dual-boot the XBoxOne to a SteamBox mode and then you will have more games available for it. Share technology with Valve and have Valve help you with your Windows problems. Gabe Newell can help you make a Windows that doesn't stink.
Consider supporting a second OS other than Windows, adopt a version of Linux or Android and port a lot of your Microsoft apps over to it. Have it as an option in case your users don't like Windows 8.X or Windows RT, and then you can still sell your hardware to them with the second OS on it to sell even more. If you cannot beat them, join them.