NIH? Vulkan was released nearly a year after DX12. And DX12 follows a long line of DirectX versions.

Also... OpenGL has kind of always sucked compared to DirectX. There is no reason for Microsoft to abandon 25+ years of support because finally we have a competitive open standard for Direct3D.

And on that note, you are just complaining about Direct3D. There are a ton of DirectX APIs for things that aren't graphics, like sound (XAudio), raytracing (DXR), storage (DirectStorage), machine learning (DirectML), and many more. Vulkan doesn't really attempt most of these other DirectX features. So... you're asking Microsoft to abandon Direct3D for Vulkan, and have everyone use a Vulkan/DirectX hybrid, which sounds awful.