supp99: the reason gog.com exists is because the average gamer is functionally retarded in terms of how not to spend money and reward bad business practices.
LootHunter: WHAT?!
Steam, online drm in diablo 3 and starcraft and other games is because people feed these games money. Before mass internet penetration of highspeed interent was wide enough, you got the entire game to run on your computer. Game companies have been slowly cutting out game functionality and holding program code hostage on servers at their companies headquarters.
In the past, games like quake 3, unreal tournament, descent, warcraft 2, etc, didn't have any online DRM in them. AKA you could always play the games multiplayer over lan, etc, no need for a connection to play single player, etc.
GOG.COM exists because games have become locked down under marketing bs : F2p,mmo, etc, aren't 'genres' they are forms of drm. See here with player run world of warcraft servers and legal shenanigans:
https://news.ycombinator.com/item?id=11444122 AKA imagine if id Software tried to use the courts to prevent people from hosting their own private Quake 3 and unreal tournament servers. "MMO's" are a trojan horse to prevent private server RPG's. Via clever verbal gymnastics and taking advantage of the fact most people are computer illiterate.
Technically all games should be going public domain.