Oh, I don't think Amazon is cheating. The whole point of disintermediation is to be more efficient and drive down prices. I'm certain prices will be lower under King Bezos, and perhaps payments to authors will stay high (though that's far less certain).
It's important to consider that Amazon has always behaved quite consistently. Even when it had 90% of the ebook market, it was the one pushing to keep prices down. In its other markets (cloud services, physical books, other goods), evidence suggests that it tries to cut prices as much as possible. I'd go so far as to say it's part of Amazon's culture. I don't think they know how to have a big fat margin on something. It'd make them itchy, like their very own fat middleman waiting to be crushed.
So my issue isn't that Amazon is waiting patiently to pump up their prices once they have enough market share. It's more that having no competition is dangerous in itself. Google and Valve, for example, are two companies that I like immensely, and I think they do a great job in their respective markets. Yet Google can arbitrarily cut off access to my email, and Valve can do the same with my games. Both have been known to use these powers when it makes sense to them. I'd change providers, but everyone else, frankly, sucks.
I want there to be robust competition in e-readers, but the Kindle is too good. I want there to be robust competition for e-bookstores but Amazon always has the best prices. There's a kind of bittersweet ambivalence in knowing that the industry leader is there because they're a clever company doing it right, but still wishing that someone else was there to challenge them. Nobody's right always, or forever.