Knowledge Management is more important than CA
An authentic - that means, in simple words: not easy to be copied - Competitive Advantage in the contemporary - that means: complex and continuously changing - environment can be only achieved by the continuous development of knowledge on every organizational level.
Hence the main duty of managers is to contribute to the creation of the proper conditions that allow this knowledge to be developed. The willingness of managers to learn new things is the first, and most essential, step.
Porter's Competitive Advantage Model is a simple theoretical construction, with little use. From the point of view that if every firm in an industry follows this model, then every kind of competition will disappear.