In the UK, MS are charging £44.99 for first party games and third party games seem to be around the £55 mark. It's even worse on the PS4 as first party games are £52.99 and third party are around £63.
Publishers would surely prefer it if we bought digital games, given that we can't sell them, trade them in, lend them to friends, or give them away. There are also benefits to the consumer, as there's the convenience of being able to buy and play a game whenever you want, you don't have to switch discs and there's no disc to get damaged, and there's the instant game switching on the Xbox One which clearly would not work if you had to get up and swap a disc.
So it begs the question, why are they charging more for digital games than disc-based games? I know that the prices for disc-based games are set by the retailer, so they might sell them under RRP and still make a profit, but publishers are aware of that. Given that you have fewer rights with a digital game, they should always be cheaper than physical media, especially if they want customers to come around to the idea of an all-digital future where a console has no disc drive and games/media are delivered only by downloads and streaming.