When it comes right down to it, Publishers are at the mercy of their authors. For Apple to really hit the industry hard, all they have to to is make it super-attractive to authors 7 content creators.

Publishers don't have to "get it" as long as Authors get it.

iTunes currently gives App creators a 30% cut. It they were to give authors 30% to publish with them instead of their traditional print publishers, I'm sure most authors would jump at the chance. 30% is SO MUCH higher than most authors ever get from print publishers.