I think a lot of people are misunderstanding what Proton actually brought to Linux gaming.
I had been running Linux exclusively for some moths in 2013-2014, and trying to get games to work on Linux felt like this : Wine is likely able to run it if you can found the right configuration, but good luck with that. I think the only game I managed to run without issues was Civilization 4, so I rolled back on Windows some time later.
Of course, Valve contributed to Wine, and projects like dxvk and others are major achievements (if a team effort), but that’s not their main contribution. Valve understood that gamers may be somewhat more tech-litterate than other people, but that making games work on Linux should be easy. And that’s what Proton was made for.
Nowadays, most games I buy on Steam work out of the box. I sometimes forget to check protondb before buying a games, and I rarely had an issue. Even if in 2018 you had to tinker a bit, you rarely needed more than to choose the correct Proton version (big up to Glorious Eggroll).
I think it’s symptomatic of the situation of the Linux Desktop : technically, it’s where it needs to be. But there is still a gap in accessibility and easiness. Tinkering is nice, but you should not have to do it to have something that works.
If by “mental illness” this graph refers to the effects on the mind of the person who study it, then it’s dreadfully accurate.