As someone that works daily with Java and .NET platforms, C# still has a better stories around AOT and value types.
Also Sun really bombed their Java Gaming initiative (who remembers that JavaONE?) with C# becoming the C++'s complement in most studios.
It's a problem with the entire design type, which has been shown throughout computing history to not work that well.
And why use C# when the Java ecosystem is pretty much the same tooling wise? C# feels like a 1.2x better Java, which isn't enough.