In practice, how many developers write C# on a non Windows platform? I'd say a very, very tiny minority.
On the other hand, Java is being written on all platforms and being deployed on many as well.
Plenty do - think of deploying c# web services on Linux servers / containers.
I write C# on Linux and I am basically the only person I know who does that.
Whether that effort pays off, only time will tell.
Plenty do - think of deploying c# web services on Linux servers / containers.