Then there’re quality issues. If you search internets for “Windows Vulkan issue” you’ll find many end users with crashing games, game developers with crashing game engines https://github.com/godotengine/godot/issues/100807 recommendations to update drivers or disable some Vulkan layers in registry, etc.
On Windows, Vulkan is simply not as reliable as D3D. The reasons include market share, D3D being a requirement to render the desktop, D3D runtime being a part of the OS supported by Microsoft (Vulkan relies solely on GPU vendors), and D3D being older (first version of VK spec released in 2016, D3D11 is from 2009).
Another thing, on Linux, the situation with Vulkan support is less than ideal for mobile and embedded systems. Some embedded ARM SoCs only support GLES 3.1 (which BTW is not too far from D3D 11.0 feature-wise) but not Vulkan.
Unless you are running Windows, in which case it doesn’t. Intel simply has not made a driver.
Yep exactly. While Vulkan API is well defined and mostly stable, there is no guarantee in Linux implementation will also be stable. Moreover Khronos graphics APIs only deal with the stuff after you allocated a buffer and did all the handshakes with the OS and GPU drivers. On Linux none of those have API / ABI / runtime configuration stability guarantees. Basically it works until only one of the libraries in the chain breaks the compatibility.
All Linuxes I'm familiar with run Mesa, which gives you OpenGL and Vulkan.