To making a point clear, in the view of programming. Of course you can compare API. Both DX11 and 12 are graphic API. It cannot be, that a newer API uses more VRAM to a point the game is unplayable. What if you use Vulkan instead? the game is not unplayable in Linux, because you don’t need translation at all.
In any software industry there always comparison of API. In particular, graphic industry, Vulkan is often compared to DirectX, in all aspects, VRAM, overhead etc…
API is algorithms to do the same things in the same field. There is always can be better algorithms to reduce resource, increase performance.