DirectX 12 and Windows 8, what is the difficulty in porting?

Question

Programming

Windows 10 and Windows 8/8.1 are very similar, so I'm wondering why someone doesn't port directx12 to windows 8/8.1 in the future. What prevents this? What are the difficulties? What is the impossibility?
I would like an answer on the merits with arguments, and not "put 10y and that's it" or "what can't you do yourself?".
I ask the question because it is interesting what are the difficulties and impossibility of this.

Answer 1

in Windows 8/8.1, there is simply no way to use the DirectX 12 API due to the lack of a bunch of components, and most importantly, this system core does not support requests from DirectX 12

Answer 2

This is a commercial move by Microsoft, aimed at the speedy transition of all sevens and eights to Win 10. Technically, I think it's not worth it for the small-soft ones to transfer DirectX 12 even to Windows XP.
There is such a term vendor lock , so in this case we have OS lock.

Answer 3

Because the program itself needs to determine (or even give the user a choice) versions of DirectX.