So, what you're saying is that Nokia needed to reject a platform where they could differentiate themselves, but where it would require hard work, and embrace a platform where as a manufacturer they cannot differentiate themselves, with limitations even imposed on the hardware profile (yes, that joke about Windows phones having three buttons - guess which ones - finally came true). Of course, Nokia can differentiate themselves on the camera optics and sensor, and we see that with the PureView hype, but a manufacturer can do that and more with an Android handset.
The principal argument for rejecting the Android brand, as opposed to the technological platform, is that it gave Nokia the ability to deliver their own services instead of things like Google Maps. However, that doesn't need a tie-up with Microsoft, and a generic non-Google Android-based platform could have delivered much of the same services. Even a warmed-over Ovi Store would have been starting at the same level - close to zero - as Microsoft's offering, so it wouldn't have been like Nokia would have been throwing away that advantage.