.net can't compete with C++ (or lower level C) and all the support and frameworks that are out there. Neither .net language , c# or visual basic, are particularly performant or widely supported outside of the MS world (and now maybe ubuntu). C# is a managed language, like for instance Java (which is truly cross platform), and there I see a certain competition.
But much newer developments, for instance the much more flexible Python-ecosystem recently, will imo make such proprietary things obsolete, if they aren't already. I won't invest a single second in it.
Edit, gosh, I already did with the writing here :-)