I've been in the computer and IT industry in some form for over 20 years. I've seen a lot of changes come and go -- some I've embraced, some I've just dealt with, some I've beat my skull on a wall wondering WTF?!?!
Windows 8 was, in all ways, a very What The Fuck?!?! product. Microsoft did it so that they could increase their revenue stream and lock-in potential - not so they could increase the user experience. There is no situation in this world which you shove a phone/tablet interface onto a desktop or laptop computer with touchscreen penetration rates in those markets of, what?, 2 or 3%? It was bad idea from the beginning and it is still a bad idea now. When most users resort to third party software to give them back the interface that WORKS on desktop/laptop environments and/or adoption of the new operating system is only because users are being given no other choice, then the system was badly designed.
Fortune 1000/500/100 companies are NOT adopting Windows 8.x. Why in the hell would they want the lost productivity from a user being forced to learn a new interface that is not user friendly or conducive to a work environment? They don't. Which is one major reason Dell and HP both started offering Windows 7 Pro installed on Windows 8.x Pro downgraded systems for business.
Stardock is making money, even at $4.99 a pop, for Start8 as a replacement for Windows 8.x sorta-not-really-a-start menu. That says a lot about the state of Windows 8.x adoption and usability.
Even smaller companies that I deal with or have consulted for avoid Windows 8.x and use Windows 7. I've dealt with some hard-headed people who ask why it is cheaper to buy Windows 8 than 7 or "Why aren't we using the latest version?" and so on -- until I sit a laptop in front of them with a standard, out-of-the-box Windows 8.x configuration on it and tell them "Please turn the laptop off without using the power switch." Then I ask them if they could turn their Windows 7 laptops off right out of the box. You guessed it, they said YES, they could turn it off with no problems and I point out the lost productivity from their users needing to be trained on how the access everything and learning how to use the new interface(s). They always purchase Windows 7 systems. By the way, this puts LESS money in my pocket as a consultant because my company would be the ones training them to use Windows 8.x.
Windows 9, if Microsoft has ANY sense left in their Corporate brain, will go back to Windows 7 start menu functionality and leave the Metro interface for phones and tablets. Give desktop and laptop users the interface that works and that doesn't require retraining everyone. Individual user and most small-to-medium businesses I deal with are tired of vendor lock-in. Learn from your mistakes Microsoft.