Many, many of the games that are now on GoG were for years FREELY downloadable on many different abandonware sites. They weren't being sold anymore, their studios had shutdown, there were no challenges to have them taken down. They were forgotten about by all but the fans who wanted just to play them.
Suddenly, those sites started linking you to GoG and they CHARGED you for them. But where did GoG get all of these many games? You trying to tell me they had ALL the originals, they scanned ALL those manuals, and THEY cracked them?
GoG got those games from pirates, just like the schoolkids did. Consider GoG's geographical location, also. Not exactly a rich area with a healthy respect for copyright....
GOG actually gets permission to sell the games from the Copyright Holders, presumably, those folk have archived games they also give to GOG. This is why NOLF is not for sale on GOG, nobody knows who owns it, so GOG can't sell it. Implying that GOG rips off abandonware sites is hilarious.
RPG Spotlight: Avadon 2: The Corruption http://www.gog.com/game/avadon_2_the_corruption Short Summary: http://pastebin.com/bRprvvKn