If it's true about publishers keeping prices high to keep retailers happy that is ridiculous, sales lost from high street retail to Steam still end up in the publisher's pocket. It's not Steam's fault that they've discovered a more viable business than HMV or whoever.
PC is only a portion of the market and consoles cannot be digitally distributed. At the end of the day they still need to get retailers to stock large amounts of console games and sending out some pc copies too is hardly going to stetch resources. Retailers hold all the cards, they sell the consoles, they sell the games, they sell the accessories, direct across the counter. Its in a publishers best interest to get the best deal for themselves and currently that means pandering to the retailers.