switch to vulkan and stop playing with this direct x nonsense.
make additional eye candy optional ( not available when not possible) Then players who can take advantage of it, can choose to and nobody has to be sad that their platform is being negatively impacted by eye candy they dont want or can't use.
A ton of effort and time and money went into VR and an obscenely small portion of the population plays with it. So it's not like there's not precedent for including features only a small subsection will be able to use. Things like raytracing which will be cross-manufacturer soon can be implementd to give laser beams and stars better lighting effects. etc etc.
But the most important thing is to convert the engine to vulkan and get away from .net 4.0 and move to .net core which is better supported in proton (since they seem unwilling to do a proper port to linux). My framerate in proton is not hitting below 11ms and it makes an otherwise seemless linux vr experience a bit less than optimal (something my hardware would otherwise have no issue with doing on a vive hmd and a 3900x and amd 5700xt setup)
Sad to break this to you... that would not solve anything... only increase costs.... as they would STILL NEED DirectX for their XBox version, just like they need to use PSGL on Playstation.... or they would have to introduce the same in-between layers you currently complain about for the running it on Linux....
So using DirectX on Windows is more cost effective, and since Apple decided to drop OpenGL and thus Vulcan support for their own Metal, there is no cost savings in switching over to OpenGL/Vulcan. Then that Linux on the desktop is still a to small platform, so that is a pretty hard sell to justify the costs to rewrite for that reason alone...
I do not see any reason at the moment to drop suppor for the current gen consoles when next generation releaseses, so that means that they still need to support that platform, and that also goes with the current setup with the Windows version, as even if hte next generation consoles gets raytracing support, the majority of pc players would still not have any raytracing capable hardware for many years to come.
We also have the significant performance hit that raytracing creates, I am not hopeful that supposedly raytracing support next gen consoles will get is more efficient than the current raytracing support NVidia has and the simple fact that NVidia still have launched new cards without raytracing support is a bit telling...
If we use Steam hardware survey to get some trends, it is a bit telling that the two most popular GPUs to use is GTX 1060 (20%) and GTX 1050TI (9%), we need to move down the list to #6 to find the first RTX card, RTX 2060 (3%) and then #10 for the second RTX 20709 (1.9%). So with no entry level cards from Nvidia with raytracing support, and we are still waiting for AMD to add raytracing support, we are still several years away from a wide adoption of raytracing.... and then we have the lackluster support by the game developers, as there is very little incentive to add raytracing support, and the current support appears to have been added because NVidia paid for the implementation... do you think NVidia will pay FDev to implement Raytracing?