3. Linux technically stays an option but is unable to run apps without NT underneath, and nobody writes plain Linux apps because of market effects
Weak because people could still write apps for just Linux, plausible because convincing people to divert effort to the MS way would work and is classic EEE.
No one in their right mind would right linux apps targeted to run WSL only. Even if they do, it would never capture the market of pure linux. Also any modifications done to linux should be GPLd hence i don’t think thats a problem either.
Your use of "extinguish" describes a situation where you can use exactly what you have now, in exactly the way you're doing now? And the terrible thing which "extinguish" means to you is "future people who might have given me free stuff might not, and it will be Microsoft's fault"? And not only that, but the way MS will "convince people to divert effort" is by making something people want more? And that is somehow terribly unfair?
The current world is that there are programs written for Linux distributions with certain subsystems (audio, window manager, systemd, etc) which don't work on other distributions without those subsystems. People who ignore binary blob video card drivers, etc. A Microsoft Ubuntu with DirectX that only runs in WSL would be just another thing like that. It would be practically no different to "macOS is UNIX but you can't run all macOS programs on other Unixes" which hasn't extinguished Linux or Unix.
Even moreso when people who want to write for DirectX can do so for Windows. Why would those people target DirectX on Linux which only runs on WSL? And if it doesn't only run on WSL, let's say DirectX on Linux works on any Ubuntu and Valve use it for Steam and gaming on Linux becomes massively popular by targetting DirectX for video ... how do you then connect to "nobody writes plain Linux apps because 3D games are an option" and from there to "and now despite being massively more popular, Linux is extinguished and this is bad because even though I can run literally any other distribution and write and run my own software and all previous software, I can no longer be bothered to and that's both bad and Microsoft's fault"?
2. People write "Linux" apps that require directx
3. Linux technically stays an option but is unable to run apps without NT underneath, and nobody writes plain Linux apps because of market effects
Weak because people could still write apps for just Linux, plausible because convincing people to divert effort to the MS way would work and is classic EEE.