No publisher is interested in releasing their AAA game without DRM, so GOG is only a place for non AAA games (mostly +10 years old). I'll not count Witcher 3 in this case.
But their client has many cool features where I believe it can be a great addition to Steam (NOT replacing it! but thats what they also dont want).
The cross play feature is pretty cool and I'm glad Valve is supporting it. I'm not really a fan of Origin because it's Steam in a different case but this client, GOG Galaxy, is going into the right direction but not trying to do the same, instead to do something that fits into the missing parts.
It will take time before that is possible, once the majority of the playerbase has moved to a new client they will have to go with the flow as they say.
I am personally done using Steam there is just too many restrictions and who in their right mind would pay 80 dollars for a game when you can get it for 20 on gog, achievements and trading cards have been a incentive to keep using steam, no more.