I pontificated about this
at length, elsewhere: Apple is not going to do what it would take to make etextbooks really useful, and will fall into the same traps that all the other attempts did.
They won't make them accessible to students with disabilities, which will make them ineligible for required public school use. They won't add the software features that are needed to make e-textbooks actually *better* than physical ones, rather than a trade-off of weight-vs-usability. And they won't be getting content from the current publishers who are fighting hard to hold onto their dwindling hardcover market.
So they'll have a swarm of self-published and tiny-indie-press textbooks, some of which will be awesome--but you won't have any way of knowing which those are, because they can only be sold for the iPad, so only iBooks buyers will review them. And they'll only sell to people who can afford a $500+ piece of delicate hardware in their school supplies.
This is not an attempt to improve the academic world & bring it into the digital era; it's an attempt to get lucrative hardware contracts with schools that aren't aware what they're buying and what it won't do.