Defining “sustainability” is trickier. For an advantage to be sustained, your competitors must not be able to duplicate it. Or, more precisely, they must not be able to duplicate the resources underlying it. For that you must possess what I term an “isolating mechanism,” such as a patent giving its holder the legally enforceable right to monopolize the use of a technology for a time.2 More complex forms of isolating mechanisms include reputations, commercial and social relationships, network effects,* dramatic economies of scale, and tacit knowledge and skill gained through experience.
