I have not missed, just haven't seen too many caring about it on the Windows game development forums.
> You can also use the Vulkan API today on iOS and OS X via a third-party library that translates between the Vulkan APIs and Metal, called MoltenVK.[0]
Zero advantages versus middleware engines.
I guess you visit wrong forums. All major engine developers are busy with it.
Those game engines support the graphics APIs from, PS3, PS4, PSP, PSP Vita, Wii, 3DS, OpenGL, DX9, DX10, DX11, DX12, WebGL, Metal, Vulkan.
Adding support for Vulkan is just yet another bullet point on that list, just like they are busy adding Metal support, as it was discussed at Unite LA.
The people that actually use those engines to make games, don't care what APIs are abstracted by those engines, as long as, their game is fast, takes full advantage of the GPU and targets the game system they want to sell to.
Vulkan is widely available on Windows, not sure how you missed that.
You can also use the Vulkan API today on iOS and OS X via a third-party library that translates between the Vulkan APIs and Metal, called MoltenVK.[0]
MoltenVK is not complete, but it covers the majority of the functionality (including SPIR-V shader ingestion) and I don't see any technical roadblocks to most of the remaining work.
[0] https://moltengl.com/moltenvk/