blotunga: I don't think they'll make Galaxy mandatory. As for those threatening to switch to Steam, go ahead, make GabeN richer and help him establish his monopoly on PC gaming.
Breja: I honestly don't get people who say they are going to do that. "What, you require me to use a client?! No way! I'm going to switch to that other store that requires me to use a client!"
Well it is pretty simple, Breja.
By overwhelming majority of consent the Steam client is vastly superior to Galaxy.
The number of games available on Steam dwarfs that of GOG.
Steam offers early Access.
Steam gives smaller developers a chance.
The price to get a game on Steam is often cheaper than on GOG with sale discounts being larger and sales in general being larger.
Steam has a bunch of games that I wish I could get DRM free and on GOG that I can't because GOG rejected them, will never pick them up or can't because of DRM requirements. Games like Mushihimesama, Fire Pro Wrestling World. Pac-Man Championship Edition DX, The Pinball Arcade, Planet Coaster.
So if they all are available on Steam, but not GOG and both require a client why use GOG?