The C# ecosystem is such a nice place to be. Libraries, frameworks, tooling, cross-platform support, development tooling, extensions, powerful robust languages - why would anyone want to give that up in favor of a Google property. No thanks.
Microsoft institutionally had a "does not play well with others" attitude to the point of stark figurative murderousness as we saw in SCO v. The World during the Ballmer years ... and as for "robustness", the one signal failing of Nadella is quality.... I could make a case it's as risky an option in the medium and long term as these other ones, and confidently state it will take at least a decades before a lot of us maybe trust Microsoft's good will outside its Windows ecosystem, hindering wider adaptation.
It's a first class citizen in terms of cross-platform compatibility. And if you don't like Visual Studio on Windows or Mac, there's VS Code (which obviously runs on Linux as well), you can always pay for Rider (which is great btw.)