If M$ releases a dx13 where the api is worse and the primary feature is copilot integration we might see more vulkan native games. So far they have been smarter than that...

Tbh I've always has better luck with Proton versus native builds.

And it is true that performance via Proton can be better than on Windows, so it isn't accurate that there is a performance penalty. In my experience it's usually the opposite. Shader precaching is one major reason.

The success of Proton has pretty much killed native Linux builds

Honestly, the Linux ecosystem is so fragmented that Win32 is the best API for targeting Linux.

There's not really a performance penalty for Proton. It isn't an emulator (Wine Is Not An Emulator); rather it's a translation layer. It translates the machine code into something your system understands and runs it natively. It isn't creating a fake version of the hardware that runs it, like an emulator does. In fact, Proton sometimes has a performance increase because of the translation. It translates to Vulkan, which is often more performant.