What publishers have no good way of knowing about directly is what happens to their book after it is sold. They can get a little information out of public libraries. They can maybe get some sense of what's going on in the used market, especially now that so much of it is online. They certainly have zero sense of how many times that original buyer re-reads that book, not much sense of how many of her friends she loans it out to, what happens at yard sales and so forth.
Some publishers have an inkling of what's happening to that book after it is sold once. Romance novels have more lives than proverbial cats. They're read by the original buyers, sometimes many, many times. They're passed to friends in bags, like outgrown baby clothes and collections of Playboy. Then they go to paperback exchanges ("normal" used book stores refuse to carry them), swap sites, Goodwill, etc. Romance novels are cheap the first time, and they get a crazy number of users and uses for each paperback copy. Needless to say, Harlequin is "platform agnostic" when it comes to e-books. They GET that e-books have a huge barrier to transfer. Stop that chain right in its tracks, er, so to speak. Sorry about that mixed metaphor but let me tell you a typical romance novel contains much worse prose. I know. I read a lot of them. They're very happy to sell that first, flush (as in, has enough money to buy several romance novels a month new) user e-books for less than she was paying for them _because then she won't give them to her less-flush friends, who will have to buy them elsewhere_.
I think it's very hard for anyone to figure the price of the second through nth reader of a given book. Amazon probably has about as good an idea as anyone, between selling used books and having an ungodly amount of information about the personal book buying habits of individual consumers. Amazon's interests align partly with the publisher, in that Amazon wants to collect every time a reader wants to read a new-to-them book. Amazon isn't trying to collect for each re-read by an individual (apparently SOMEONE learned from Div-X); they're greedy, but they aren't crazy. In a way, they're collecting money on sales that publishers had to give up on, when libraries established a right to lend books, when used book sales were established as legal. Depending on one's perspective, that could be a big bonus to a publisher -- people who once bought paper might buy an e-book priced between paper and hardcover, same with used buyers, and all the way downstream to the person who once bought used paperbacks, now buying e-books priced below new paper because it's been out for a while. But it is currently being seen by publishers as a huge minus: people who once bought new hardcover (even discounted hardcover), now paying $9.99. In hordes. And bragging about it to all their friends. That looks like Amazon is trying to siphon off enough from the publisher to sell their $359 gadget.
And sure. They are. I still think there's enough downstream for everyone to do okay, if not as well or even better. But I don't know. If anyone knows, it's Amazon, or maybe Harlequin. Because remember, when Harlequin authors hit it big and go to a different publisher and get their name above the title or even a hardcover, don't forget what Harlequin does: republishes their early work as a Mira paperback. With very little evidence to the unwary that it isn't just-written by the hot author of the day. Harlequin knows a lot about the reading habits of the people out there who read the most books a year, and how to intercept their dollars for things they've already sold. And sold. And loaned. And given away. And worn out. And Harlequin doesn't give a shit what your platform is. All they know is, they want to sell you their stuff on it.