As we noted earlier, Windows 8's reception to date has been tepid at best. As much of a train-wreck that many considered Vista to be, even it had greater adoption six months after launch. There are multiple factors that can be blamed here, with one at the forefront being Microsoft's new-fangled Start screen. Many have considered that interface to be ideal for tablets, not desktops, and that's something I can't disagree with. But on the topic of tablets, the Windows 8 situation hasn't fared much better than on the desktop.
According to Mark Whittard, managing director at Toshiba Australia, Microsoft "confused" consumers with its dual-OS approach; that is, Windows 8 and Windows RT. This doesn't boil down to just the obvious differences, but even pricing, as he states: "They were going even cheaper than the traditional RRP (recommended retail price), so the gap wasn't just the $100 or $200 from non-touch to touch, it was $400, and the customer's going: 'Hang on a sec, that's starting to get unpalatable, that price differential, and I'm not sure about this Windows 8 thing.'"
Those are some great points, but I'd also like to think that the fact that there are two Windows OSes that look identical but are actually quite different could have had something to do with it also. As enthusiasts, noting the differences isn't going to be too difficult; but to a regular consumer, two tablets that appear to offer the exact same OS but are called something different can be confusing. It can become even more confusing if you try to explain limitations of the RT variant due to the use of an ARM (vs. x86) processor (be sure to read our review of Microsoft Surface with Windows RT here).
With the response Windows RT in particular has seen, it'll be interesting to see if Microsoft continues to keep its ARM-based variant in its future plans. However, given the sheer amount of manpower it would have taken Microsoft to port the bulk of the OS over to ARM, it's unlikely that the company will go out without a fight.