Having written even basic tools in native code for Linux and run into compatibility issues (glibc versions, ugh), I'm not surprised.
Wine is probably the best cross-distro Linux platform, especially for closed source products that don't get compiled for every specific repo. Flatpak/AppImage would also work but that lacks the raw system access that many games depend on (even if that system access is secretly emulated by Wine).
Which makes me both happy and concerned. On one hand, I am finally able to use my main computer for gaming without having to deal with dual booting nor emulation (in the VW sense). On the other, Proton completely kills native Linux porting. Amnesia The Bunker being released only in Windows despite the developers' long story supporting Linux was likely influenced by this.
I’ve grown comfortable with the idea that the win32 API is simply a gaming runtime now. I’m okay with this situation because A) I don’t have to give up any performance (or at least none that I’ve been able to measure) and B) the Proton/WINE stack is still open source all the way down.
It could certainly be argued that I’m doing some mental gymnastics here, but I look at Proton/WINE as simply being part of the game engine. Traditional engines like Unity/Unreal have all kinds of translation layers and indirection.
If it works, it works. Proton isn't going anywhere; even if development is abandoned old versions of Proton will still exist, so games that forewent native Linux support in favor of Proton will still work.
On the other hand, I have Linux releases from GOG which no longer run (sadly, I cannot remember the specific example where I first encountered this). It is expecting some specific version of library X. Theoretically, I could run it if I booted up an older Ubuntu release (assuming I could still install all of the dependencies/drivers?).
According to other sources (ProtonDB), about 80% of a much larger subset of Steam games run on Linux (some worse than others) - next milestone is 90% I guess, a couple of years down the road.
Some of those games 'require' an unofficial version of Steam's Proton which includes support for features in the underlying components that the official version can't ship.
Mostly it's an issue for video codecs in games (patents are the issue here), or games that use a less popular API. (From windows! Which has ~3 decades of APIs from multiple vendors. Let alone 10s (10-100 IDK) different ways of playing back audio or a video, or both at the same time.)
Some of the changes are simply more bleeding edge patches or game specific tweaks that are included faster than official releases include them.
In theory it doesn't matter, but in practice there are issues. On other distros like stock Ubuntu you won't have Flatpak out of the box and would need to set that up. Likewise on some distros you would have to worry about alternative repos or package architectures.
You get a recent kernel + mesa + vulkan which means a recent proton shipped with steam can use all the extensions it wants for efficiency.
Recent kernels also contain a few features specifically designed to aid wine.
No, Steam comes with everything you need for games. Other launcher work great using Lutris.
Apps like Lutris, Spotify Yuzu are on the Discover app store which uses flatpak. Flatpak is on many distros already installed or can be installed manually.
(PS: The Steam Deck's OS isn't even Arch Linux. It's based on it and uses Arch packages, but updates come from Valve through their own update mechanism with a read only file system. It's like calling Ubuntu Debian just because Ubuntu pulls packages from Debian Testing.)
