Critics who think Amazon is killing retail should talk to the millions of businesses/products that were rejected by retail gatekeepers and only exist today because of Amazon’s ‘infinite shelf space.’
Retail had been artificially stifled by more than a century of a ‘Big Man’ (gatekeeper) system. Amazon Marketplace has spurred a Cambrian explosion of SKUs and the businesses who create them. ‘The Origin of Wealth’ captures this problem perfectly: 
‘Buyers’ at big retailers used to decide which products would be given the chance to be market-tested. All sorts of incentive problems here, but the effect was increased concentration of wealth & power for large vendors (e.g. P&G).
A retailer (e.g. Walmart) had to pass the initial survival threshold by offering a selection of products that consumers want. But once passed, the gatekeeper system maximizes wealth and power of retailer & vendors - not economic best interest of consumers.
What we’re seeing today is one of the greatest wealth transfers in history from big companies like P&G to thousands of small brands as the (Amazon) market(place) removes the fitness-function-distortion of gatekeepers and passes voting power into the hands of consumers.
A time may come where Amazon is stifling innovation, but we are only seeing the beginning of what’s possible with a true marketplace for products. Stopping this redistribution of wealth and power now would be a colossal mistake.
Final thoughts: biggest threat to continued innovation is Amazon’s ad platform. Once marketers start gaming system, evolutionary process gets extremely distorted. The purpose is to give newcomers a chance to get noticed (otherwise too far down in rankings)...
...since it is otherwise ~impossible to overcome incumbent reviews and rankings. One option is for Amazon to make reviews ephemeral - reviews are archived after one year. This ensures that reviews are current and that new SKUs have a shot at competing.
