On one thing we agree: a few things companies do seems baffling if not altogether misguided. But then, it's entirely possible that these top notch MBA's just play a game we don't even know the rules of. Reminds me of my attempts at inferring the rules of cricket by watching a few games on TV.
This said, even with my very limited knowledge in the field, I think that what Elop did was remarkable given the initial conditions. Symbian was falling hard, and had been for years, Android was already an overcrowded market, with several strong market leaders. Not a nice place to be the new kid on the block.
By jumping on WP with both feet, Nokia obtained an immediate injection of hard cash and a huge safety net, as Microsoft cannot afford to let Nokia to go under, at least for a few years to come. This was the best outcome possible for Nokia's stakeholders, employees included (alas, not all of them) but it could only happen through a full committment to the platform. All in all, a solid A in my books.