MS offers support I would assume for DX12 and constantly wroks on the platform and software. I would also hazard a guess that since the majorty of games hit xbox one that they will be dx 12 because of that. PS4 doesn't use vulkanIn my layman's understanding I can see no reason to ever use DX12 when Vulkan does basically the same thing across all platforms. Clearly I am missing something as it seems the number of DX12 games vastly outnumbers the number of Vulkan games (Doom is the only one?).
I wasn't expecting SQ42 till early next year and at that just a few of the levels with more released over the year. With the switch to vulkan I expect it not to happen till late 2018 .