Over time the work was obviously done for Mantle → Gl Next → Vulkan. And that's becasue AMD were positive about this idea. Their initial presentation of Mantle

Over time the work was obviously done for Mantle → Gl Next → Vulkan. And that's becasue AMD were positive about this idea. Their initial presentation of Mantle was in that vein, i.e. to kickstart the progress of the common API. MS just decided to do that whole thing for their NIH in parallel using parts of Mantle practically verbatim. It wouldn't have been possible without AMD basically allowing it. See: https://x.com/renderpipeline/status/581086347450007553 https://x.com/renderpipeline/status/581086347450007553 I.e. I don't see any reason here for MS not to collaborate on Vulkan instead, besides the usual lock-in approach.