Ultimately it's not GOGs fault that Hello Games isn't just making a Lobby system for starting a Game together, where you get a Code, share it with your friends, they join the lobby, everyone is happy.
Also G(ood)O(ld)G(ames) the middle part is important here.
On GOG you get games without DRM for the full (if you can't wait), or a reasonable price (when they have a sale). You get offline installers and most importantly: Games that would not run in their original 'Final Patched' version from the Developer on modern Operating Systems.
It is not Steam, it can't be Steam. Thats a good thing.
GOG dropped the name Good Old Games officially when they decided to start selling new games. However, it seems like that didn't drop it in spirit, since we only play old games here.
Also, not being Steam isn't a good thing here, where we never received the Atlas Rises multiplayer since we're not Steam.