Odd Amazon pricing for a Kindle book

Now I know Amazon plays some games with pricing. Experiments happen. No problem.However I ran into a very strange thing when they had some odd pricing:

Look at the paperback versus the Kindle prices. With the Kindle they have no inventory, no shipping, nothing. The physical book on the other hand needs space for the book in the warehouse. They need to ship it (which since I'm an Amazon prime member I get for free). And at the end of it I have a completely unencumbered physical artifact I can do just about anything with.I might excuse them if they sold for the same price -- the authors, editors and publishers all need to put food on the table. But to sell the digital version for more?!What gives Amazon? I thought you were trying to get more people on the Kindle?I wound up getting the hard copy even though I love my Kindle.