Perhaps they asked the test users the wrong questions? The W8 release had the feel of groupthink about it, like they'd convinced themselves this was the way to go without checking what everybody else thought. I was an early adopter as I happened to be buying a PC soon after the launch, and remember 8.0 as a real mess out of the box, with the conventional and Metro UIs crudely nailed together. Metro wasn't bad by itself, but there were jarring shifts between the two environments, especially as MS has decided to 'expose' the user to their new toy by having it replace the Start men, and registering a bunch of file types to Metro apps. Settings were arbitrarily divided between the Control Panel and the new PC Settings app (something we're still stuck with in W10). Things that should have been obvious weren't easily discoverable, and the hot corner thing was just irritating. Fortunately, most of this was easily tamed with Classic Shell and judicious re-registering of common file types to more sensible applications, after which W8 turned out to be fast and stable, and rather less irritating than W10 is now with its frequent forced 'upgrades'.
It's even harder to get away with this sort of thing in the Linux world, where attempts to make the original version of Gnome 3 and Ubuntu's Unity the mainstream standards were pretty much doomed to failure by the vast choice of competing distributions and desktop environments. In the end, all this did was to give us even more choice by encouraging developers to revive Gnome 2 as MATE and create Cinnamon as yet another fork of the Gnome 3 shell. Mint got quite a boost by supporting the former and developing the latter, while more conservative distributions waited until Gnome 3 was sensibly re-jigged with extensions to give a more traditional UI. Even Ubuntu has now ditched Unity for a revised Gnome 3 desktop, and there's a MATE spinoff that has become my current favourite Linux distro.
And now, once again, everything looks suspiciously like Windows 95...