Earlier quoted context omitted.
DirectX 12 isn't just much more like Vulkan, it's so shockingly similar, it's basically Vulkan. It's jarring when you read it for the first time because you ask yourself why it even exists, but a second later, you realize it's so Microsoft can own their own graphics interface, too. I could be remembering this incorrectly, but that's the impression I remember.
They look similar because both D3D12 and Vulkan have been 'influenced' by Mantle (Vulkan more strongly than D3D12 though). Vulkan was released after both Metal and D3D12 btw.
While flohofwoe certainly knows this, for the others,
"Khronos is free to take as many pages as it wants out of the Mantle playbook, and AMD will impose no restrictions, nor will it charge any licensing fees."