C# is definitely popular for game development, but saying no other language comes close does not seem to be true. Looking at the most popular game engines and frameworks, it seems to be about as represented as anything else.
Game engines:
Unreal - C++, Unity - C#, Godot - GDScript (Python) + second-class C# support
We don't know for sure what AAA companies rolling their own engines use, but the industry standard would be written in C++, exposing C++ for programmers and Lua for non-programmers/modders.