All Amazon is going to have in a few years is Type A assholes who are willing to kill themselves and they'll have no creatives, no inventors and nobody who actually is innovating. They'll have people who happily work 100 hour weeks to reduce the delay after clicking "Buy Now" and nobody coming up with the next Kindle.
Just noticing my own consumption patterns. I find myself buying far less from Amazon than I used to. I go the public library for most books now, keeping just a few in my Kindle app for reading while traveling or reference. I stream music now instead of buying it. I reverse showroom - Go to Best Buy, look at a few products, then read the reviews on Amazon to determine which one to buy since BB will match.
Amazon's big advantage in the early days was their ability to sell new products to consumers without sales tax. Bezos leveraged this to build mindshare and brand, but now he doesn't really have that huge advantage over other retailers. Sooner or later Amazon will be average internet retailer - Lots of products for sale with low margins. That may be one reason they push their people so hard, the profit margins they have now are not sustainable. Could even turn into another Sears.