I mean at that point you can just make backups of your steam games too. A lot work straight from the exe and for the rest there are steam simulators.
A small minority of GOG games have DRM, a majority of Steam games have a form of DRM. “Use a simulator” isn’t a solution, I shouldn’t need a third party program to play the games I paid for.
Also there’s a pretty big difference between downloading the installer and backing up the installed files, one is an intended backup solution, the other is a workaround.