Has it really been that long? Apparently so. Valve originally announced their rebranding of Steam Play with Proton back on August 21st, 2018. Seems like a good time for a quick reflection being halfway to a decade old now with the tech that gave rise to the Steam Deck.
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.