Earlier quoted context omitted.
I'm sure it was difficult, but you can already ship C# code using Xamarin, no need to wait for Microsoft.
Xamarin is a bit of a hack. What we really need is a cross platform solid (i.e. not javascript) language supported natively. What would be ideal would be that Apple, Google and Microsoft sit together and agree on a common language and GUI API that would work on Android, iOS, Windows, MacOS and Linux natively.
What's more likely these days is Google entering the desktop space (x86) by merging it with mobile (e.g. Andromeda). Pretty sure that OS could grab 30% of new laptops in a heartbeat (think: almost free for manufacturers: no Win license).
Meanwhile, I'm pretty sure Apple will do its thing (did they fix Gmail on Mail yet?) Though I think Swift, if it were in "the state of C#/.NET" as worded above, would eventually become a great candidate for a high level common language. Somehow I don't think Apple is trying, their open-sourcing seems to end at "reassurance" (stacks can't die if you can maintain the packages, b/c oss, yay).