The writing. The editing. The marketing.
...and they pick up 98 percent of the profits, if any. With self-publishing (not just amazon) typically over 50 percent off the bottom goes to the author. This is an absolute necessary change to the industry. It will result in 2 or 3 fewer JK Rowlings, but 100s of thousands fewer outrages.
[1] http://www.antipope.org/charlie/blog-static/2010/04/common-m...
As with any business there are 'good' publishers and 'bad' publishers, and the Amazon move (and others like it) could lead to less friction in the publishing business which will certainly boost quantity but it may (as Charlie posits) negatively effect quality as well.
The future may end up being 'karmic gods' to coin a phrase, kind of like kingmakers of old but people or organizations which, by applying a seal of approval or blessing on a work can immediately levitate it above the sea of choices, which will replace what 'publishers' do today. These people may appear to be 'super - Agents' as I've heard them referred to or 'pressless publishers' (a take on fabless semiconductor companies which already have a model that works well for them).
We should see artisan printers arising. Its a new business where you work with an author/agent to have exclusive right to put into physical form a work, perhaps leather bound on acid free paper or glue bound onto newsprint.
Amazon has an excellent chance of continuing to disrupt here and kill publishers outright. Certainly the disruption in the market is going to move around where the money goes and it will affect the net total value of a given work. Much of that value may simply disappear (which is to say authors make more and consumers pay less but a giant middle-industry no longer exists so those folks don't get salaries and their suppliers don't sell product etc etc). The economics of information march relentlessly on.
They just fund books, at terms which would shock the conscience if they weren't so well-established. (If a book was a startup, the typical offer is something like "We'll put in $5k at a pre-money valuation of $1k and, by the way, we're going to claw that $5k back, too. Also, we're going to contractually lock you up from talking to other investors for your next three companies. You owe it to us, because we're rescuing you from not being published.") I will not mourn their passing, as either a reader or an oft-suggested author.
From what I've noticed, royalties are generally about 10% of gross against advances (if any), or $1 on a $10 soft-cover. The publisher spends money on the acquisition, editing, printing, and distribution; in brick-and-morter land, this isn't cheap. Remember that the store needs to make a couple of bucks, too.
Additionally, major retailers include a buyback clause—if the book doesn't sell, the retailer can sell up to something like 15% of the initial purchase order back to the publisher. The publisher often forwards your share of that burden into your royalty payment schedule.
Though, ultimately, while authors might get screwed financially in a lot of ways, publishing does, as a consumer, keep a lot of crap out of your purchasing decisions. Publishers (on the whole) do provide a lot of value to you: are you going to buy Gruen's AWESOME guide to Ruby or The Ruby Programming Language from O'Reilly Publishing with its venerable woodcut cover treatment?
If you're trying to get your work out there (which is why people write in the first place) you're probably willing to take the traditional publishing deal.
Publishers are helpful, but the game is inextricably rigged in their favor, which sucks.
We should compare notes.
More like $0.50 on a $10 soft-cover--the wholesale discount is likely somewhere between 40 and 55%.