If we want to go more in a general direction - where Amazons push for more vertical integration is set to create some real problems, if coupled with economies of scale and the still very young concept of digital goods, we can do that as well. I'm encouraged to write about this - because I just read a corresponding blog article that nudged me into this direction - but maybe wasnt written in a way that would correspond to the realities of millennials.
In essence - it is the question, why an Amazon premium membership not only should buy us two day shipping, but also storage for our pictures, music streaming, exclusive TV series to bingewatch and of course - free book rentals. And a discounted Washington Post membership - and why not - better black friday deals as well.
So the reason Amazon is doing this, are economies of scale. Margins on digital goods tend to be very slim in general, but at scale - they are wonderful, because you do the work one time, and then hit distribute to millions. Also, economies of scale are great, because you dont care about the message so much (in a sense "quality"), you care about contact frequency, about the size of the ecosystem. And if you keep margins low enough you dont have to worry about startup competition, because the entry costs to compete with highly vertically integrated companies that communicate this as being a value for the consumer - is immensely high.
Which by the way - is also part of the reason, why the US is getting chip and pin almost a decade after the rest of the developed world.

Funny story - maybe look it up sometime.
Now the point where the issues for the consumer start showing is, when content creation and content distribution start to merge, interests get conflicted.
Amazon kicking out Nvidia, Google and other competitors from their distribution platform is a move prompted by their interest to play a role in the content game.
Amazon kicking out Kodi from their App Store ecosystem can be seen as a move to prevent any forms of consumption on their devices, where they arent set up to take a cut of the profits. ("Our mp3 player only plays content streams!")
Amazon creating a new book format only they can produce and distribute, and controlling every aspect from layout to inherent properties (DRM gets pushed onto public domain books) to the date it is published, should be seen as an attempt to get exclusive benefits (forms of ownership) over the eBook medium as well.
In the Amazon theme park you get wonderfully cheep image hosting with your two day delivery plan, you get exclusive TV entertainment, produced by studios that were set up, because you really should buy more Kindle tablets, boxes, sticks and readers, but you shouldnt expect to know, that out there, there is a Google as well, that isnt a "content partner", you shouldnt expect that on a Fire TV you would be able to watch or discover content that, in any way, ventures outside the prebuild ecosystem for you to watch or discover content (called a storefront), and on Kindles - you really should buy the books Amazon can exclusively build - because, they are the best.
Now - back to the quality aspect. Because Amazon doesnt want to carry the risk that comes with really running an online library for example, they look at new ways to structure value - that are more in their favor. If you lend a book for example, in this new economy, this shouldnt count as having shown a token of interest - instead Amazon wants to pay by pages read. Presumably - because their metrics show, that on eReaders that would shift the value more towards the popular selfpublishing topics - that is - markets they already own.
Is the Amazon Appstore a good Appstore (curation, discovery, diversity).
Has the selfpublishing model (including their promotional campaigns to surface new content) resulted in something that challenges the older concepts in terms of quality, profits for authors at large, or diversity? (Similar problem to music streaming serivces?)
On the TV content front - I dont have to ask - they select their scripts on the basis of being "not yet mainstream", "slightly controversial" but "overall socially accepted" - which, by their own accounts (speaking in front of German media summits), regarding their metrics shows - that those have the best potential of becoming hits.
Now is this - and what aspects of that are - in our larger cultural interest?
They buy Jeremy Clarkson (brand core: enfant terrible, journalist) presumably for the content aspect, but then have him create commercials for the Fire TV and Drone delivery instead. In their own storytelling they address this, by having him say - that he had a lot of free time this summer - and really got to like his Fire TV during that time. It was so easy.
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https://www.youtube.com/watch?v=S7mGbRkUP7Q (Popular german commercial for AOL that follows the exact same storybook. Produced in 1999.

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Is Amazon content really set up to be able to become "the best content possible"? Is them exclusively owning the most current (and presumably all future) eBook format on the Kindle (most popular reading device for long format content) a good thing.
If there is as much as counter viewpoint - this is the time where I challenge you to formulate it. Write a similar posting to this one - or my posting before this one.
Dont just feel cosy in a world - where you seem to get more and more, without having to pay for any of it. But only for all of it. It's so easy. And by actually loosing options. And certain product features.