>Indeed, and the rumours are that Project Astoria worked too well which scared Microsoft. If Android apps "just worked" on Windows then why would developers bother using their new Universal Windows Platform.

This is categorically false. You only need to visit the windows phone reddit to see all of the complaints on how poorly implemented it was, how it affected the performance of the phone and the app compatibility issues.

Microsoft's attempt to put Android apps on windows phone and their harebrained idea to replace Google services with their services, within the app, were all failures and not because it would have cannibalized their native apps, but rather they just couldn't pull it off.