On this page: http://techcrunch.com/2014/04/02/microsoft-updates-visual-st...
There is this quote:
Microsoft also today announced that Visual Studio 2013 has sold over 3.7 million copies since its release less than five months ago. That makes it the fastest-selling release of Visual Studio to date.
Based on those numbers and the fact that Visual Studio prices range from about $1,000.00 for VS Professional up to $13,000.00 for VS Ultimate, I'd say they make quite a bit of money of C#, .Net (and of course C++ as well).