Meanwhile with Steam you click once and the game runs, since they jumped through all the hoops for over a decade to make that work, while GOG sat around and still hides their MSDOS games in a self extracting Windows executable, that neither runs on DOS nor Win9x.
Anyway, back to the point: DRM-free is just a teeny tiny fraction of what might prevent you from running a game.
Also it's not like GOG is digital rights management free in the purest sense: You still have to have an account and they still track what you own, it just isn't enforced at the .exe level, but it makes things like used games sales still impossible, since you can't relinquish or transfer your ownership.
Overly focusing on DRM-free just misses how the soft landscape has changed in the last two decades and what things actually matter.
Stop spreading misinformation. Even if you're a non-techie you can add non-Steam games to Steam's launcher (my extremely tech illiterate friend just did this) and they'll run with Proton.
It comes down to a game by game basis, and it's still extremely rare (outside of recent 2025/2026 anticheat AAA title stuff) that any game would have a Linux specific/impacting patch.