Not to defend the publishers (furthest thing from my mind), but I've never really seen this argument brought up:
The big publishers are all trying to build their own digital distribution platforms, because none of them want to give a percentage to Steam or GOG or Amazon or whoever. But then they realize even though in theory digital distribution should be cheaper than physical, it actually has costs they probably didn't have to deal with before. With physical games, GameStop, Wal-mart and the other retailers take on the cost of storage, shelving, and some of the front-line marketing, customer service, complaints and most importantly, customer cash transactions.
When a game publisher creates a digital distribution platform, they go from being a publisher who lets dedicated retail businesses sell their content, to a bona fide online retailer. Which puts them on the hook for:
i) Server farms to store the content and customer data
ii) Bandwidth for the downloading of content
iii) applications to handle secure online retail transactions
iv) the technical and customer service expertise to run an online retail business
v) the legal advice to handle retail transactions pretty much anywhere in the world
Now, the major publishers might have some transferable expertise from running online multiplayer servers and such, but I think most of the applicable expertise of online retail has until recently been held by the hardware manufacturers (MS/Sony/Nintendo) or those who threw their hats into digital distribution early (Valve, GOG, Games for Windows, etc.). So the publishers have probably been blindsided by how expensive digital distribution actually is and are keeping the prices high as a result.
What the big publishers actually need to do is:
i) Accept that they're not cut out for the retail business, and learn how to do business with Valve and Amazon et al the same way they did with GameStop and Wal-mart, or
ii) Understand that Valve and the other early adopters were able to get away with mistakes early on because they had little competition. If they want to be successful online retailers, they should use the advantage of the late adopter and learn from the early adopters' mistakes without making them all over again yourself, but also realize that building the infrastructure in the first place is going to be really expensive at first. But if they don't build platforms at least comparable to Steam, why should anyone take them seriously?
Is there something to this, or I have completely missed the boat somewhere?