That's a very big call, & one I reckon you're likely to be wrong about...
Android had only just started to hit it's stride when news of it's pending acquisition of Motorola trickled out, we didn't see all the vendors running away.
There was a small hit for a brief period, but that's it....
MS hasn't got anywhere near as much to lose, post merger I'm sure it'll find ways to keep OEM's interested, & to get new ones to come on-board.

I do agree though that they need to fundamentally change WP's rigidity, it was modelled way too heavily on iOS.
They need to move closer in approximation to Android, it seems they're well aware of that & have started moving in that direction.
Still, it's likely it'll always be too rigid for most maemo.org/Android users tastes...

Anyway, we digress.....