Vulkan is an open standard, and anyone is free to write their own open-source implementation. This is exactly the same as OpenGL - OpenGL is an open standard,

Vulkan is an open standard, and anyone is free to write their own open-source implementation. This is exactly the same as OpenGL - OpenGL is an open standard, and has an open-source implementation by the name of [Mesa](http://www.mesa3d.org/ http://www.mesa3d.org/). As other people have said, OpenGL is to Vulkan as C# is to C. For large-scale engine developers, it's quite clear which you'd want to use, under-the-hood. Besides, just writing the C# runtime environment in C makes an awful lot of sense.