Think about it, Apple never planned the native application Store we have today. They were forced into it by the genius hackers who made amazing apps for the first jailbroken iPhone.
When introducing the first iPhone, Steve said web applications are everything you needed to enable rich application functionality.
Hello iBooks 2
Besides the chrome web store, there aren't any popular web app selling platforms out there. And definitely not mobile.
iBooks author is actually a visual IDE
Bigger than the App store
The chargeable web
I'm not sure if this is Apple's goal, but they are actually creating a chargeable version of the web, from the second iBooks author was out, most content websites can easily create a chargeable version of their content.