I don't think that you are quite right here. Whilst VAT is levied, ebooks should be still be much cheaper to produce and sell than the printed text version. What I have noticed is that, initially, pricing is set against that of the hard back and when a paper back version is printed then, with very few exceptions, the ebook price is lowered. But there is no economic justification for this - so I am inclined to go with the 'extreme greed' conclusion.
I have no adopted the policy of awarding an automatic one star to any ebook which is priced too high - as a way of registering a protest.
I feel similar frustrations on this count. The lack of a competitive market currently in ebooks (books for kindle largely only available from Amazon) is making the situation worse since Publishers seem able to fix the prices of their books. Price fixing is NOT acceptable.