Wine was already mostly at that point a couple of years ago. It used to involve a lot of manual fiddling, but in the later days of DX9, the majority of games worked out of the box.

DX11 is where things went wrong again, and mainline Wine has been quite slow to implement DX10+ features. There have been some great projects like DXVK which have made DX11 games playable in Wine, as well as a lot of work going on in different branches and patches of Wine to improve certain functionality. Fortunately Proton brings all of these together, and has all of this configuration dealt with for you.

After a period of stagnation and not being able to play any games released in the last few years, we're back to the point where brand new AAA games can run with Wine/Proton with solid framerates - I was very surprised to see Monster Hunter World running well in Proton within a few days of release.

DRM and anti-cheat remains the biggest blocker though. Some Denuvo games run, but many don't. Anything using BattlEye or Easy Anti-Cheat won't work, or if you're lucky, the anti-cheat might let you in, but then ban you for a false positive. I hope these can be solved at some point, but the nature of Wine works and how anti-cheat identifies tampering means they'll probably never play nice together.