This is going to sound churlish...
Well, it is churlish. But, compared to free? We'll see how I go with the Amazon system, but what they're competing with in terms of delivery is whatever doesn't cost as much as they make me pay--and not just in terms of money. Sticking with one book seller, like the Kindle will supposedly make me do, is a cost. Credit card security questions are a cost. Not being able to transfer to my phone is a cost. Opportunity is a cost--is the Amazon system sufficient? If I stick with them, do I lose out on other kinds of books? I don't know yet. Will I have to deal with ads?
I think I recall reading somewhere that online content market experience is showing that lots of people are fine with shopping in a market like Amazon (or Netflix or whatever). They like ads too. They like that everything's all set up for them and they're willing to pay what to them is a small cost. The success of paid music streaming and buying seems to bear this out. Is downloading more like breakage and wasteage than lost earnings?
The Chinese system is interesting. They have websites with original content. The authors crank out chapters per week which people download for tiny sums. It's a brutal system for the authors, apparently. But if you get famous you can make money until you burn out. The thing is, apparently people do pay. I actually don't know if those get pirated as well.