It is kind of amusing how similar this is to the network neutrality debate -- i.e. comcast's dispute with netflix affecting comcast/netflix customer content delivery -- yet with decidedly old-fashioned media.
The digital side of amazon story is not interesting in the slightest. The only real story is them leveraging their print marketplace to put pressure on a digital agreement. It's an abusive hardball tactic but one that large brick and mortar bookstores have done in past.
This story shows that publishers are really obsolete. The production doesn't matter anymore with Print-On-Demand and Digital. The main services they offer are distribution and promotion. Many of the publishers have offloaded their distribution to amazon (and the like) and unless you're a big author the promotion is virtually non-existent. One could also argue they provide editing but now there are editors for hire to support indie writers.