Have you even looked at the linked patchnotes? I don’t think that “Added support for GameCube controller rumble when the adapter is in PC mode” is something linus torvalds fixed personally in the linux kernel lmao.

And, for the sake of the argument, let’s say all of those improvements are upstream linux kernel improvements. Then valve still has to pull them, build a new build and push it, something that no major company can be assed to do. And that effort is still commendable.