I don't really think it is about refusing to learn other tools. My opinion is about choice. I work with C# 90% of the time. I also happen to use other language

I don't really think it is about refusing to learn other tools. My opinion is about choice. I work with C# 90% of the time. I also happen to use other languages fluently. I think is a matter of choice.(I also have to admit that there are some developers that just don't want to get out of the comfort zone, but I don't think ALL C3 developers should be judged this way). For example, I have used Xamarin products for a some projects, and it makes a lot more sense for me, to use C# with Xamarin products than Objective-C. That is a language I have been avoiding for a long time. And the reasons are not the scope of this comment. On the Android side I am definitely using Java. So cutting to the chase, I think that for a company to support C# without Microsoft involvement is not bad, and it doesn't mean that ALL developers are lazy or mediocre, it just means more choices for developers. Specially if you have big investments in Software developed on C# (either .Net or Mono).