[karyon]

> For one, all shaders would need to be converted from HLSL to GLSL

There are transpilers (cross-compilers?) that translate from HLSL to GLSL and back and into every other shading language out there, there's really a lot of such tools.

> Secondly as I understand it the Vulkan API is much more low level and barebones than DirectX

Vulkan is about as low-level as Direct3D 12, which has not much in common with Direct3D 11 and lower, just like Vulkan has not much in common with OpenGL. OpenGL is (very roughly) equivalent to Direct3D 11, and Vulkan is more like Direct3d 12. The thing is that switching between the similar APIs is a lot of work, but does not require large refactorings, whereas switching from OpenGL/Direct3D11 to Vulkan/D3d12 requires more fundamental work.