>When one buyer represents 50-60% of sales, ... One party to the negotiation can walk away; the other cannot.
I don't follow the logic here. Your fatalistic assessment assumes Hachette (and other publishers) are paralyzed and cannot adapt. However, the business world isn't static therefore Hachette can walk away. (If not this particular contract renewal because of timing pressure then at least the next one -- if they have a smart strategy.)
If amazon has 60% of sales, it was the book publishers who willingly signed previous business deals to allow amazon to become that dominant. Likewise, those book publishers can put on their business-thinking hats and figure out how to make amazon less powerful.
Victim thinking: ok, amazon wants to pay us less for our books. Since we're helpless deer in the headlights, what do we do?
Business thinking: ok, we got our executive team in a conference room here. The CEO says, "this is where all you vice presidents and MBAs earn your salaries. Give me a business plan to lessen amazon's pricing power over us." Options:
1) Rethink/reprioritize other reseller relationships and offer better terms to Barnes & Noble, Apple iBooks, etc
2) Open our own online book store. Talk to other publishers about starting a consortium or joint venture to create a new online book store to sell direct.
3) Maybe Google Inc is also interested in partnering with us to beat amazon.
4) Call CEO of Sony and tell him we want help his eReader beat Kindle by offering exclusive titles just for that device.
5) dozens of other creative business ideas...
If all the big publishers want to, they can join forces and pull all their book titles from amazon. Amazon is then left with just the self-published CreateSpace titles. The book publishers made voluntary deals to get them into this position of weakness and likewise, they can start making voluntary strategic moves to get them out of it.
Airlines used to pay a big commission to travel agents. The airlines used the emergence of the internet to reduce commissions to agents. In this case the vendor (airlines) got more leverage than the reseller (travel agents). However, cruise ships still rely on travel agents for the bulk of their bookings. Maybe the relative positions of market power will change. Maybe not. Businesses can adapt and change if they want to.
All the articles from New York Times, salon.com, author blogs, etc sympathizing with the book publishers have not convinced me that Hachette is a helpless victim of amazon dominance.