GOG has the only serous competitor to Steam IMO. It's the only big store that's well behaved enough for people to actually want to use it.
The gaming industry will ALWAYS use DRM.
This will keep GOG a niche player.
I remember the old game launcher that was called Desura?, which a lot of those third-party keys sites would sell keys for, and it's no longer around. So one of the main concerns with these online platforms is them disappearing and losing all your stuff.
Quite frankly, I am happy that GOG exists for this niche. It would be less "sabotaging" if consumers would actually vote in their own interests. However, this has been shown time and time again to never happen, sadly.