From http://journal.bookfinder.com/2009/03/breakdown-of-book-costs.html (Slightly old)...
Based on a list price of $27.95
- $3.55 - Pre-preduction - This amount covers editors, graphic designers, and the like
- $2.83 - Printing - Ink, glue, paper, etc
- $2.00 - Marketing - Book tour, NYT Book Review ad, printing and shipping galleys to journalists
- $2.80 - Wholesaler - The take of the middlemen who handle distribution for publishers
- $4.19 - Author Royalties - A bestseller like Grisham will net about 15% in royalties, lesser known authors get less. Subtract the author's agent fees and self-employment taxes from that, too.
- $12.58 - profit for the retailer.
In the case of an ebook, you're removing the $2.83 in printing.
You might be removing some of the wholesaling cost, but you might be using Ingram to do your wholesaling if you're a big company. If you're self-publishing, you might be using something like BookBaby or Smashwords. Yes, you can go to KDP and register your own book yourself, but if you're selling in multiple places or selling multiple books, you're going to use a middle-man to handle cataloging, recordkeeping, and listing things in multiple places. If it's more than $2.80 in headaches, you use a distributor.
Marketing, pre-production, royalties all don't change. (Or they get squeezed, and you get exactly what's going on right now, which is authors complaining "they don't pay us or market us or do a good job editing us like the good old days.")
As for that $12.58 of supposed profit, here's the interesting thing - Amazon doesn't sell books at list price. John Grisham's new book, The Racketeer, is an example. List price: $28.95. Yours for only $19.81 in paper.
I'm not saying that ebook prices should be equal to the price of a printed book, but removing the printing doesn't suddenly make a book cost a dollar or even five dollars.