I was in Fry's Electronics last week, went to the laptop section, and couldn't find any touchscreen Windows devices in their sea of laptops they had on display. I had to ask a salesman, and he had to point out to me the one they had on display.
I imagine that once touchscreen devices and monitors become the standard, people will be more inclined to go with Windows 8, so I haven't written off its success yet.
Or, I guess the pessimistic flip-side to that is that the market has spoken, and there isn't a strong demand for such devices running Windows 8?