This is true to some extent — though it’s on commission and, well, we are all familiar with the tale of the goose that laid the golden eggs, aren’t we?
Human nature dictates that greed is a far more potent motivation than ethics, but to this point, there’s been efforts to prevent the ease of theft in business cases. Competition for Amazon’s services would probably be the right mechanism here, if authors (superstar or not :)) flocked to another distributor who promised better security for their work — or even a modicum of care about it — they would be in a different position, wouldn’t they?
Anyway, it struck me as something some folks might not know much about and for those who are keen to be published or to self-publish, something else to think about?