Because they’re not the “default”. Most folks stick with whatever comes on their device by default; Edge on Windows, Safari on MacOS/iOS, Chrome on Android, etc. Anything beyond just picking it up and turning it on requires forethought and effort, which most users don’t care about.
Just one or two, and it’s been quite a while. One of them, I don’t remember which, it was because of some anti cheat that caused the issue.
If I can’t get it working on Linux I get a refund. For the past two years my Steam year in reviews have showed 100% of my play time was on either Steam Deck or desktop Linux.
I remember that! I had Unreal Tournament 2004 and it technically had a native Linux version but it wasn’t on the CD. You had to extract most of the files from the CD and go download the Linux executable file from the unreal website to drop into the installation folder.
Proton is just Wine from Valve. They add their own fixes and patches and whatnot and have an “experimental” branch you can try with games that don’t work right away, but it’s just Wine. Everything Valve does to Proton eventually makes it way back upstream to Wine proper. One reason Valve may not make it available for MacOS themselves is because they’re basing their SteamOS on Linux, and while MacOS and Linux are both Unix “like”, MacOS was/is more based on BSD, so the system calls may not always line up or work exactly the same when translating them. I do think however that Proton, or a modified version of it at least, is what Apple’s game development kit thingy leverages.
After Steam officially released its native Linux client I played Half Life 1, 2 and “Brutal Legend” because they all had native Linux ports before proton was a thing. Before that I remember playing games like Sauerbraten (quake like fps), Battle for Wesnoth (my wife and I still play this together), Frozen Bubble, LBreakout2 and several other Linux native games.
I’m using CalyxOS and it’s pre-installed as a system app, so this seems like something that’s being built in at the AOSP level of development.
Planned obsolescence
I’ve thought about it; but with a wife and two kids it would be difficult if not impossible to pick up and move somewhere else and start all over.