Comment by Const-me

> run games through a Proton-like shim even on Windows

Already happening, to an extent. Specifically, modern Intel GPUs do not support DirectX 9 in hardware, yet legacy apps run fine. The readme.txt they ship with the drivers contains a paragraph which starts with the following text: “SOFTWARE: dxvk The zlib/libpng License” DXVK is a library which implements Direct3D on top of Vulkan, and an important component of SteamOS.