Windows 8 has the potential to be a colossal flop. I'm not the first person to say that. But even though some of the dynamics are the same as the Vista release, Win-8 will be a flop for slightly different reasons than Vista. On the plus side, it might cause people to finally upgrade to Windows 7, and put the final nail in the coffins of XP and IE6.
Vista was a relatively minor tweak to the Windows XP user interface. Yes, some people hated the changes, but they weren't major. (Perhaps it was just dissimilar enough to be annoying?) What really killed Vista was that the initial release performed more poorly than XP (--subsequently fixed), and that pretty much all software other than DirectX 10+ games will run on both Vista and XP, offering few technical benefits to an upgrade. And really, since Microsoft botched the DX10.0 release, my understanding is that DX10 developer uptake was a little slow at first, thus compounding the problem. (Some DX10.0 hardware sold with new Vista and Vista-capable machines was not 10.1 capable.)
Win-8 is some ways the opposite of Vista. The user interface changes are dramatic, but the performance benchmarks are looking pretty good. At least Microsoft learned that one lesson from the Vista experience.
I'm certainly not blazing any new paths by suggesting that the “Metro” interface for Windows 8 might be okay for a tablet/touch interface, but is out-of-place on a desktop. That's not the only problem with Win-8, but it bears mentioning. I won't be retreading the ground covered by others, but I've seen more than enough online video of new users trying to get back to the Start screen to know that there's a serious problem.
Maybe they can band-aid the UI before release. Maybe they can allow Metro-style apps to run in a windowed environment. The least they can do is to allow the desktop/laptop user to permanently revert back to the classic interface. This would not be without precedent. The Windows 95 installer had an option to use the 3.11 task manager. Windows XP can easily be made to look like Win-9x. Windows 7 isn't quite as flexible, but a number of the more annoying changes can be toned down, such as the control panel. If Metro is so awesome, won't we all just use it and stop griping, just as we have since the mid 90s? Well, until the introduction of the Office ribbon – a user interface catastrophe that will look mild compared to Metro on the desktop.
But Win-8 has another set of problems that have nothing to do with the UI. Win-8 will suffer from extreme market fragmentation, more so than I think many realize. Yes, there will be two flavors of desktop, plus the “RT” Windows for ARM devices. But it doesn't stop there. There will actually be four desktop flavors, two feature sets multiplied by two processor architectures, 32-bit and 64-bit. Plus RT. Legacy-style applications won't run on RT. 64 bit applications won't run in a 32 bit environment (-leading developers to continue to target 32 bit environments, and once again shortchanging the "WoW64" crowd), and hardware drivers will of course continue to be incompatible between 32 and 64 bit environments.
And then it gets tricky.
There will of course be ARM tablets and phones. There will also be x86 and x86-64 “tablets” (and convertibles), capable of running legacy applications. And, the animals that I'm not sure have been accounted for, ARM devices masquerading as low end desktop and notebook/netbook machines.
It's that last category of devices that I think has the greatest potential to make consumers hate Microsoft. Unsophisticated consumers will buy a “Windows” desktop-looking (or notebook-looking) device that won't run anything they want. They'll run Office 15 (-or a version of it), a plugin-disabled Internet Explorer 10, and Angry Birds. And that will be about it.
But back to Vista. When word got out that Vista sucked, consumers and IT-departments alike scrambled to upgrade all their 2000 and 9x systems to newer XP systems, looking to bypass Vista entirely. This will almost certainly happen again. Those still hanging on to their XP systems (-we have XP where I work) will slam through a Win-7 upgrade. Even though I already have a Win-7 laptop, I'm strongly considering getting a nice Win-7 desktop for some light-to-moderate gaming. (Ain't no way Diablo 3 is gonna run on my lappy.) We'll get mainstream support for Win-7 into 2015, and extended support until 2020. Should Win-8 turn out to not be the giant turd I believe it will be, the machine I'll buy will be upgrade-worthy, and I'll drop the extra hundred bucks or whatever on an OS-upgrade.