I think there are two parts to this problem. First, there aren't any content delivery networks that currently can rival the traditional ones, not from a publisher perspective at least. Selling content through retailers is still the best way to reach a lot of customers. Second, don't underestimate the publishers need for control. That's what they do, they acquire rights to distribute things and distribute them.

So, what's the solution? Create a content distribution system that is easy(widespread, user friendly, open?) and let's the publishers control the distribution, but not necessarily by being involved. Whatever retailers, or wholesalers, should be a part of this is hard to say. But seems likely.