Actually, I think the better question is: when will we see Android apps on Windows (Phone)?
If Microsoft hasn’t given up on Windows Phone already (which I refuse to believe), this is the only realistic solution of closing the app gap and bringing Windows Phone forward.
Another good indicator for that “convergence” might also be the effort that Microsoft is currently putting into Android with their own apps. If you search for apps released by Microsoft Corporation on the Google Play Store, you get this picture:
Draw your own conclusions. I am pretty sure where this is going ..