And many of those publishers are now also publishing on Steam because it's close to a monopoly. Like Blizzard recently with Overwatch and soon their other games. And Microsoft published games.
Once WoW is on Steam, then this argument might hold water. Overwatch being put on steam was a desperate attempt at boosting the player count of a game suffering severe player drop-off. Steam was simply an untapped well of users to draw from for Blizzard.
