They actually know better, and acknowledge it in their advertising, although subtly.
"Own it today on Blu-Ray or DVD!"
They have advertised the product for PURCHASE, not LEASE. It's OWNED by the buyer, not LICENSED to them. After making that statement in their advertising, they can not enforce a "non-transferable license" unless we LET them.
eBooks SHOULD cost less, because costs of printing, distribution and storage are effectively ZERO. Previous analysis of this demonstrates that approximately 65% of the cost of a hardback is eliminated by the eBook (http://yro.slashdot.org/story/12/03/08/1655202/publishers-warned-on-ebook-prices). So a hardback priced at $25 should be about $9 as an eBook.
I refer you to http://baen.com/ Best ebook sellers on the planet, in my opinion.
If the publishers were selling eBooks at a 65% markdown compared to their hardbacks, they would see less piracy. Baen books are hardly ever found on piracy sites, according to the publisher.
I am fully in favor of the first sale doctrine and the existence of a used market in eBooks and other digital media. But I also see the arguments opposing duplication. There is no question in MY mind that I OWN these piles of bits; but until the technology catches up, what I see as the ethical choice is to DELETE materials I transfer to others, to deal directly with the original publishers when I cannot ensure my seller is deleting their copy, and only do business with companies whose business practice reflects my own opinions. Like Baen.
It's the same problem that the printing press created: "anybody" could print and sell these books. It's what the copyright developed to control. By current copyright law, Ben Franklin was a pirate.