what if that company with 0% market share want
1) to eliminate retail price competition ("the prices will be the same") so it can effectively compete on price
2) guarantee 30% margin
and to get there, it needs at least 4 Major Publishers on board. And these 4 Major Publishers will only get on board if Apple could guarantee that they are not alone. In other word, 1 Publisher with 12% market share won't get Amazon to move away from $9.99 but 5 Publishers with 60% market share will be large enough that Amazon will have to raise the price of best sellers to $12.99 / $14.99.
DOJ evidence:
"You are absolutely correct: we've always known that unless other publishers follow us, there's no chance of success in getting Amazon to change its pricing practices."
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Penguin David Shanks: "My orders from London. You must have the fourth major or we can't be in the announcement."
Apple Eddy Cue: "Hopefully this is not an issue but if it is I will call you at 4pm. It would be a huge mistake to miss this if we have 3."
"No change here, he is waiting for the others to sign. We have executables ready to sign but he wants an assurance that he is 1 of 4 before signing."
"Once previous two are signed, I will head to their offices to get this one signed."
1) Apple doesn't care about the retail price (as long as it's not excessive to the point where no one would want to buy ebooks). They don't mind if publishers want to sell at 9.99 or even less. Apple just wants to pay 70% of whatever the retail price is. In fact, Apple was clear that publishers cannot set the price of ebooks as high as paper books because there wouldn't be a market for it. Why don't you quote Eddy Cue's slide where he makes this point? Publishers could easily have just told Apple "no".
Some people seem to forget that Apple is primarily in the business of selling high margin hardware (iPhones, iPads, Macs, etc.). Their iTunes business is simply there to create more demand for Apple hardware products. That's why they kept trying to push music publishers to maintain LOWER prices, not higher prices. That's also why they warned publishers they can't price books more than $12.99 or $14.99 or there wouldn't be a viable ebook market.
After taking a 30% cut and paying overhead, Apple's profit margin is in the low single digits (this was again in one of the slides). In short, Apple has no incentive to drive UP the price of ebooks. They want to sell as many ebooks as possible so people would buy more iPads/iPhones/iPods.
2) MFN clause is used in many retail businesses by those with enough marketshare that wholesalers are willing to go along with the MFN clause. Considering the fact that Apple had 0% marketshare of the ebook business, and had not even released the iPad or any other normal sized ereader yet, and Amazon controlled 90% of the ebook market, Apple really had no leverage over the publishers and the publishers could have easily refused the MFN clause and froze Apple out of the ebook market completely.
Instead, the PUBLISHERS wanted to wrestle power away from Amazon and saw Apple as a means to do it. So, the PUBLISHERS agreed to the MFN clause in order to facilitate Apple's entry into the ebook market.
The publisher's tactic is similar to Amazon's $9.99 loss leader price strategy. Amazon is willing to sell certain books below their cost to build marketshare and bring customers in to buy other products from Amazon. An unstated motive is it also allows Amazon to bury their competition, i.e. Barnes and Noble and other ebook retailers who can't compete b/c they don't have the same cross-selling opportunities or scale as Amazon.
Similarly, the publishers knew Apple's MFN clause was a potential money losing proposition but the PUBLISHERS still decided it was good business strategy for THEM to give Apple the MFN clause because it would bring Apple into the ebook market and screw Amazon.
Did Apple want a MFN clause? Of course. Was Apple in position to force the publishers to give it to them? No. The publishers CHOSE to give it to them for their own business reasons. Apple was going to release the iPad with or without an iBook store. In fact, with the Kindle and Barnes and Noble and other ereader apps, iBooks and the iBook store is redundant.