"What is the marketplace doing to earn this percentage of my sales?" seems to be a common question asked by sellers. The last thing on their minds it would seem is the fact that the marketplace is selling their item for them and providing the infrastructure so that they don't have to handle all that PITA interaction. This is especially true of Amazon. You get a lot of value by selling on their marketplace. The high number of sales, delivered to a device that many people own and enjoy using to consume content, the trust associated with the Amazon brand and the reviews by "real people."
Exactly. His surprise seems surprising. That the company with the clear majority in the e-book market would charge more for the service of being published within that market does not seem like earth shattering news.