GOG is DRM free!
Even if GOG closed down tomorrow, I could still play the games I'd bought from them. Can the same be said for Steam?
No, I'm afraid the reasons for not using Steam are just too many. And I for one will never buy a game from Steam.
Have you really given Steam a try or just on the anti-DRM bandwagon? There's an offline mode for Steam. I can play all of my games offline a lot of times...b/c my internet kinda sucks. I understand your concern but Steam doesn't force you to go online to play your games. Perhaps I haven't gotten a game where it forces you to auto-online ID but non of my steam games forces you to do that.
