AC is 100% wrong - in fact he's got it backwards!
Apple colluded with publishers to raise the price of e-books, not lower them! The publishers have never liked that Amazon sold books cheaper than everyone else and were happy to make little or no money on them - Amazon has barely made any profit ever (check their earnings reports if you don't believe me) but the greater fool theory has kept their stock price in dot.com bubble range since the dot.com bubble burst for everyone else so they don't need to make money as they always use their shares for cash.
The publishers knew that the longer Amazon does that, the more brick and mortar bookstores get put out of business. That's why there are so many fewer than there were when Amazon started. Now Amazon was doing the same thing to e-books, pricing them so low they made little or no money, because they wanted to dominate the e-book market in the way they were dominating the physical book market.
Apple went to them and got them all to agree to set a minimum price for their books below which they couldn't be sold. They didn't have to twist any arms, the publishers all wanted this, but couldn't do it alone because they feared Amazon would quit selling their books if they went it alone and other publishers didn't match them. Apple got them all to agree "I'll do it if you all will", basically (which is collusion, and is illegal) Effectively it forced Amazon to raise their prices and start making money on their books. Unfortunately for Amazon, it meant they had no way to beat the competition by undercutting them, which is their entire strategy. Consumers didn't like it either, because e-books cost more without Amazon selling them at a no-profit price.
The DoJ stepped in, and invalidated those agreements, so Amazon can go back to undercutting everyone and making little or no money selling e-books, and Apple and the publishers are being called to the carpet for violating the law.
Amazon is playing the long game, figuring that they will eventually control the book market (both physical and e-book) so tightly that they will be able to tell the publishers what to do - and lo and behold, if you read the news they're doing just that with Hachette. They want to continue to drive down the profit that everyone else makes so the price of books becomes lower and lower so no one else can possibly compete with them. When they are utterly dominant in the book world, they'll be able to price books however they want, and collect almost all the profit. That's why their stock price is so high, everyone owning it is waiting for the day when Amazon has run all the competition out of business and quits selling stuff at a profitless margin and starts raking in monopoly profits.
When that happens, consumers will be screwed, because if they want books they won't have anyone else to buy them from but Amazon, and if Amazon charges $20 for a e-book and the author gets $1 and the publisher gets $1, well that's just too damn bad.