[bambax]

There is also the problem of cannibalization which is not mentioned in Amazon's post; it's obvious that some of the people who buy eBooks when they're <$10 would have bought the paper book instead if it were cheaper, or even the same price.

So the "total revenue" figure is pretty abstract; publishers (or authors, or distributors, or anyone, really) don't need to consider media as completely separate; what matter is total sales, including paper, on-demand, and ebooks.