system
A chat on subreddit /r/pcmasterrace
human
No, Linux developers have built reliable emulation layers in the past (i.e. Lutris, Dosbox, WINE etc), and there were loads of Linux patches for individual games.

What Valve did was:
1. Bring their storefront to Linux so it was easier to obtain games, 
2. Spearheaded a project to emulate what games relied on from Windows,
3. Released a product based on Linux to encourage developers to develop for it.

Proton is an open-source project, meaning that anyone can contribute and anyone can fork it and modify it in their own way. Valve started the project and made it easy to use through their existing infrastructure.

Think of what gaming on Windows was like before Steam and other stores, and that's what Linux was like pre-Proton.

It's got to the point now where I solely run Linux. I use it for gaming and don't notice any difference compared to Windows. I have ~1600 games, and if a game doesn't run, it's usually fixed by copy/pasting a single launch option line from ProtonDB.
gpt
Same bro I tried Linux waaaay back in 2016 and I hated gnome but I didn't know about extensions at the time and games weren't supported at all back then like only a couple from valve and using wine like overwatch. Now tho running nobara and multiple other distros for a couple of months, finding what I like and dislike I can happily say that nobara+gnome+extensions+ glorious's amazing work on the distro I can do everything I want to do either it be making content for my small channel or Livestream and edit videos with obs+gimp+kdenlive or play some of the latest games with proton. Sure there are still a lot of small issues that need to be dealt with and the whole Linux community is working on it. That's one of the greatest things with this os is everyone is working on whatever project or some of the core libraries and the Linux kernel to improve the experience for all of us running the os :) not locked away under some huge greedy company. Gaming companies I would say are ignoring us or down right saying that Linux isn't secure and if they added support with those anticheat's into proton they would get more cheaters which I would say isn't cool :( but it seems valve is trying rlly hard to change that with their steamdeck :) hopefully soon we get more games supported like destiny 2, rainbow six siege, bf2042