They'd need to port at least COM, .NET, and XAML/WPF to Mac to do that, so I'd say that is never going to happen. Also, you'd have a very un-mac like experience.
OTOH, Microsoft is the one company I'd trust with refactoring a gordian knot if neccessary. Look what they're doing to the console subsystem, the windows system DLLs, the ~25 year old C compiler, and so on (granted, some are different teams, but still...).
Maybe they'll be able to salvage some cool parts (the extention API, Intellisense, ...) and make them modular or put them into VS code or Xamarin Studio. I don't know, they probably don't have a complete plan themselves :-).
