I don't believe it would drive adoption at all. Microsoft know Windows Phone today is dead. However they still have the desktop and with UWP they hope to bridge the development gap between mobile/tablet/desktop/laptop.
Had they shipped Astoria in Windows 10 to allow Android apps to "just work" it would have destroyed their UWP strategy.
So they might get a few more Windows Phone users but they would have lost control of the new development platform and given it to Google on a silver platter. And they would never have got anywhere near the numbers Android is at.
I would be shocked if Microsoft don't bring UWP to macOS, Linux and Android (I don't see how they can with iOS) in the not-too-distant-future.
Had they shipped Astoria in Windows 10 to allow Android apps to "just work" it would have destroyed their UWP strategy.
So they might get a few more Windows Phone users but they would have lost control of the new development platform and given it to Google on a silver platter. And they would never have got anywhere near the numbers Android is at.
I would be shocked if Microsoft don't bring UWP to macOS, Linux and Android (I don't see how they can with iOS) in the not-too-distant-future.