Good lord, the mental gymnastics Apple fans go through to defend their favorite for-profit corporation...
No, the POINT is that only a handful of corporations (less than 5 probably) have that kind of leverage, so suggesting that all a developer need do is "negotiate" is ridiculous. Virtually no developer, not even a BIG one, has the kind of leverage that Amazon does. And what "extra" did Amazon have to offer? Not cutting off the sale of Apple products? That's not brining something extra to the table. That extortion. Sort of like how Apple extorts its developers with a single App Store and a grossly unfair commission structure.