A hypthesis: Languages are no mean in itself. They are used to generate programs for specific purposes on specific plattforms. The availability of the plattforms and the need to create software for them makes the language popular. C for Unix/Linux, JavaScript for the Browser, C++ for Microsoft Windows, Java for Business stuff* and Android, Ruby for Rails, Objective-C for Mac and iOS, C# for .net.
* Sun invested a billion in Java to replace the more costlier Smalltalk. Instead of competing with Sun, IBM ditched Smalltalk and just went with Java, too.