My comment is a fact, without the Windows games ecosystem, by developers living and breathing on Windows, with Windows development tools, Proton has nothing to play, even if many of Windows games are developed on top of cross-platform engines.
Unfortunely Valve failed to make native Linux gaming a reality, not even game studios targeting Android NDK bother, which has the same 3D and audio APIs as GNU/Linux.
Audio APIs on Android are completely different than on GNU/Linux.
3D was also different (OpenGL ES vs OpenGL mess), only now it's starting to become kinda the same with Vulkan.