That point of view is outdated.
Hence Roslyn, .NET Native with VC++ backend, value types improvements and safer pointers in 7.x.
There are even plans to slowly move parts of the runtime from C++ into C#, now that .NET Native is a thing.
" So, in my view, the primary trend is moving our existing C++ codebase to C#. It makes us so much more efficient and enables a broader set of .NET developers to reason about the base platform more easily and also contribute"