How's this for a conspiracy theory:

1. MS encourages Nokia to hire Elop.
2. Elop says Nokia is a "dead man walking" company. Elop announces WM7 adoption. Elop kills existing Nokia development, thus there's no way to backtrack. Stock drops.
3. Nokia announces poor sales. Stock drops.
4. Finnish investments are probably heavily in Nokia stock.
5. Nokia releases WM7 phones to poor sales. Stock drops.
6. MS announces plans to purchase Nokia to help their partner out. Finnish government will approve to aid Finnish investors.
7. MS now has phone fab and world wide distribution for WM8 phones. Think of WM8 as Xbox 360, 2nd gen after the first gen fails.

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There's no sound rationale for Nokia to put all its eggs in one basket. Why couldn't have they dropped Symbian over time and added WM7 *and* Android phones to their portfolio? HTC must be much smaller than Nokia and they seem to be fine developing phones for two OS's... and with plenty of varied models to boot! The only thing I can think of that would make Nokia/Elop do something stupid like this is if MS promised "special privileges" if they didn't develop for Android.