In my opinion With windows 8 they saw a split in the market. Consumers are becoming mobile, and producers are migrating to laptops. Rather then creating 2 perfect operating systems for both they decided to create a zipper to merge them back together. It reeks of a regressive perspective.
Microsoft still employs an army of talented engineers, and they have a successful platform. I'm a .NET developer. I'm proud of working on Windows. But I can't see their future, and I suspect neither can they.
I think that's the right approach in general, though Windows 8 may not be the right implementation. The reality is that you can no longer neatly sub-divide market segments. We're exiting the era where we can point to a device and categorize them as a phone, tablet, laptop or desktop. There is overlap between the phone and tablet categories and even more overlap between the tablet and laptop categories - and things will get more and more confusing as manufacturers experiment with designs. The upcoming Surface Pro is a great example. Is it a laptop, or an iPad-like tablet? Well, it's neither and both.