UltimateUnknown on 24 November 2016
It's because publishers will not undercut retailers for digital game prices in fear of getting less shelf space. Even though digital is pretty big now, physical sales are still the most dominant. So if a particular publisher started to sell a game for $50 on the digital store while physical copies were still $60, Gamestop and other retailers could stop selling/advertising that game or putting it on their shelves, which would be a huge hit to sales of that game.
Retailers like Gamestop have been forcing publishers to give them exclusive pre-order bonuses for a long time now and publishers don't have much choice but to oblige for this very reason. They are very dependent on retailers to sell their games.
