There are a couple issues here. It's not Apple or Amazon, but the publishers that want higher ebook prices. If publishers had not gotten their way, then NO ONE would have been able to buy ebooks until some time after the hard backs have been released. Just as it is with paperbacks.
The second issue is that ebooks are network only "things". There is no store front, no location boundary. People will shop for the cheapest price. Amazon has been willing to lose money on every ebook they sell. As such -- NO ONE ELSE would have any incentive to sell ebooks. This is not a good thing for the publisher, and it's not a good thing for the customer.
This is not new folks. It's called "dumping". You sell a product for a loss, run all your competition out of business....then you are free to jack up the prices to anything you want.
We all understand "loss leaders" where soda or milk is put on sale to get people into the store. But in Amazon's case -- the entire set of bestsellers was turned into loss leaders all the time.
So Apple says "I'll let you set your prices to whatever you want on our book store -- but only if Amazon and everyone else isn't allowed to undercut our prices". Why should Apple spend it's time and money setting up the iBookstore if the publishers are going to continue to let Amazon sell every desirable book for a loss?
People do not need to worry that the rest of economics will fail to provide downward pressure on the price of ebooks. Publishers can't set the price to $100 and just make sure that Apple and Amazon sell for that price. No one would buy them.
The publishers are going to start with a certain price and the market will teach them what is or isn't acceptable.