[jonnathanson]

I think you're giving his analysis too much credit. His point wasn't so much that the field remains wide open to startups. It was that, in his estimation, Amazon had no sustainable competitive advantage precisely because the barriers to entry into its business were (ostensibly) very low.

This is a little like saying that anyone can beat Tiger Woods, because all you need to do is pick up a golf club and practice for 10,000 hours, and golf clubs are readily accessible. While nominally and theoretically true, it's also a drastic simplification of many, many factors that have gone into making Tiger as good as he is -- and that will keep him better than most of the competition for quite some time.

Access to resources is only one very small part of business strategy. The rest is what you make of those resources, and how the advantages compound when you're making smart use of them. On the flipside, the beauty of startups is that they can, and often must, use the resources in different ways.

Furthermore, he made the fundamental mistake of thinking that Amazon was just a traditional retailer, but on the web.