Good old Games has been forced to remove the classic catalogue of Fallout games from its digital shelves, because of a change in rights that means Bethesda now owns the games in their entirety.
This is the final chapter in a multi-year batttle between Bethesda and Interplay, the latter of which was supposed to produce a Fallout MMO for the former. However Bethesda eventually argued that Interplay only owned the name Fallout and not the property which it is based around. This went back and forth for over two years, before the courts sided with Bethesda and essentially said that after December 2013, all rights for Fallout properties would go to it, despite Interplay being the original creators of the series and the first three games.
This move means that GoG can no longer sell Fallout, Fallout 2 or Fallout: Tactics, unless it strikes up a new licensing deal with Bethesda. Fortunately though, those that have previously bought the games will still be able to download them if they want to.
This could be the reason GoG recently put all three of the those games up for free during the recent Winter sale.
All three games can still be found on Steam, suggesting, as PCG points out, that ultimately Valve may have made a deal with Bethesda. It remains to be seen if a new one will be struck between the publisher and GoG. We'll have to wait and see.