Vulkan is a lower level API than Gallium so they've had to create new abstractions at the Vulkan level. This is why the ANV (Intel) driver is what everyone copy

Vulkan is a lower level API than Gallium so they've had to create new abstractions at the Vulkan level. This is why the ANV (Intel) driver is what everyone copy/pasted from, there was no shared code at the Vulkan level at that point. Over time they've taken the parts people were copy/pasting and turned them into generic things all the Vulkan drivers can call instead. Gallium is still the way everything else is implemented (OpenGL, Direct3D 9, video decoding, OpenCL) for drivers. One of those drivers is Zink which implements the Gallium OpenGL state tracker on top of Vulkan and another is D3D12 which does the same on top of Direct3D 12 (for WSL2). Not every driver supports every state tracker, in general all you can count on is some version of OpenGL to be supported (4.6 for Zink, 3.3 for D3D12).