It's all about the UI. On the upside, having active areas and (heaven help us) the "Charms Bar" invisible in order to economize on screen real estate is fine if you know where they are, but you forfeit the ability to look at the screen and see something that looks like it might do what you want. If you're running multiple 27-inch monitors at full rez, you can afford the pixels, believe me. Not so much with tablets and cell phones.
But guess what? Just because all the marketeers are squealing that tablets and cell phones are the new computing paradigm doesn't make it so. In fact, the market, especially the business and professional market, is rather conservative when it comes to user interfaces. Training time and learning curves cost money and productivity. They also really tick people off when they're mandated by Momma Micro$oft (or Auntie Apple or anyone else, for that matter) who knows what's best for you, you technology illiterate.
8.1's OK, but just that. Linux on the same machine screams. And you get to choose your own UI. Micro$oft isn't going to keep me.
Windows tops visitors to my company website, Linux is second over Mac.