C# has a higher rate of change than Java and a very strong ecosystem - albeit not quite as strong as Java. The tooling - if you pay for it - is in my opinion much better.
The thing is, the Java ecosystem is insane. What else comes close to it in breadth and quality? Python, Go, Ruby etc certainly don't. C++?
C++ yes. That is why despite its flaws and complexity, it will be around for decades to come.
Even on the places where Java and .NET languages took over C++ hegemony, it is still there on the implementation of native/extern methods and COM/UWP libraries.
Also don't forget if your favourite compiler is a LLVM/GCC frontend, many of its improvements require a bit of C++ code changes as well.
The thing is, the Java ecosystem is insane. What else comes close to it in breadth and quality? Python, Go, Ruby etc certainly don't. C++?