As far as I've been able to ascertain the author gets royalties anywhere between 8% and 15% of the cover price of a book (hardback is near universally accepted at 15% and mass market paperbacks likely hit at 8%). 45%-55% is taken by the publisher, however this includes the authors royalties and the printing costs are ~10% of the cover price. So, assuming hardback royalties and printing costs the publisher could be taking less than 20% for editing, advertising and marketing. However, it can also easily be as high as ~37%.

Now here's the very crucial part for ebooks. Distribution costs, from what I have found out, are on average 10% of cover price. A whopping 40% on average goes to the retailer.

Less printing and distribution costs, a novel should still be selling for 80% of cover price when brand new (hardback equivalence). Macmillan likely isn't being greedy here, if people who read on eBooks want novels as soon as they hit the market, then they should by rights be expected to cover the costs.

The problem with rigid pricing is that a $10 charge for brand new and 2 year old material is insane. I've picked up mass market paperbacks at $6 without a discount, but brand new novels genuinely cost $30 and beyond. Even if Amazon waived 3/4 of their cut, without distribution and publishing costs, (50% off basically) it should still be selling for between $15 and $20 for a brand new novel.

An addendum to this is that all books are unique. The prices and costs vary, for example a cookbook is far more expensive to print than a simple paperback. Kindle, in my opinion, would hold great promise when a coloured e-ink is used(/usable) for selling graphic novels and comics on. They have far higher printing costs than anything else (minor editing of both writing and art), but already retail at reasonable prices (unless you're grabbing a Frank Miller A-3 sized bastard). Potentially it could take us back to comic books retailing at $1-$2 instead of like $10.

With the mass potential for region locking and other DRM's I don't believe eBooks are currently a good thing, and they're certainly not a friend to any prolific reader. I hand some of my read books out left, right and center to anyone who wants it. I remember my mum taking entire grocery bags full of books to her work (in a hospital) where the staff used to swap books. Where's the potential for this in eBooks?

With the Kindle being constantly connected to the internet, you would expect that a single eBook could be sent between Kindles without restriction quite easily. This would mean the only hurdle left for paper-like eBook usage would be the region locking, which again sounds like an exclusively Amazon made problem. I really don't see why a US publisher would care about region locking, electronic publication rights are handled as though the internet is one entity (so it isn't to enforce the authors rights to sell it in another country or anything), where as regular publication rights are exclusive to one territory (with the US and Canada being joint). I suppose there's potential in it to prevent it damaging paper book sales in foreign countries, however eBooks are currently tailing the market by many, many months so again, I have a hard time believing this is the publishing industries idea.