[jeremyjh]

Its pretty evident from things they said in this blog post that they want to stay firmly in mainstream. They mentioned C/C++ is the only compiler supported by both platform vendors, which is important due to a "whole host of other issues" that they didn't specify. So using a compiler developed by a company that doesn't even sell commercial support would be a non-starter. Still there are commercially supported platforms that are quite mature at this point, such as Xamarin.