AMD Mantle became Vulkan. AMD Mantle precedes Apple Metal.

dagmx · on Nov 25, 2022

Mantle became Vulkan in only the most superficial of senses and when Metal came out, khronos+NVidia were banging on about AZDO OpenGL instead.

dmitriid · on Nov 25, 2022

Mantle was a proprietary AMD-only Windows-only API until AMD gave up and parts (not even the whole part) of Mantle became parts of the future Vulkun standard sometime in 2015.

So sure, sure, Apple "went out of their way to not support standardized cross-platform APIs" that didn't exist even as an idea by the time Metal was released.