Why is anyone surprised?
Movies on iTunes are more expensive than dvd's from amazon or play.com
TV shows are more expensive than box sets.
And as time goes by, the physical media gets discounted further, and a DVD you can pick up for £2.99 is still £9.99 on itunes. TV boxsets are often £10 on amazon, and £35-£40 on iTunes.
Why would iBooks be any different?
Oh, and amazon kindle ebook prices include VAT, it's not added on after or anything.
Side:
The thing I'm surprised by is all the comparion to hardbacks and hardback prices? Do people really buy only hardbacks in the USA? Most people I know always get paperback.