This is an interesting opinion piece regarding why Amazon has such significant competitive advantage over traditional retailers.
It comes down to several related issues, but can be boiled down to the fact that Amazon, in addition to its economies of scale, has multiple revenue streams. It has revenue from its computing services. It has revenue from ad sales.
These additional revenue streams are something that Amazon’s competitors are starting to sit up an notice. Walmart, for one, is signaling its intent to become an “experience platform” much in the vein of Amazon, where brands not only sell to customers but also market to them.