For many years, southwest airlines distinguished itself as the low-cost airline. now, many other low-cost competitors have entered the market. similarly, southwest was one of the first airlines to offer online ticketing. now, all airlines have online ticketing. these examples suggest that:

A single strategy is not enough to generate a sustainable competitive advantage over time.

Explanation:

The sustainable competitive advantage over time is what allows an organization to differentiate itself. If there is no differential advantage, the price becomes the protagonist. On the other hand, if the organization is able to offer something relevant and different, the perfect excuse is given to the client to make an effort to achieve it.

Markets tend to be extremely competitive except when there is a company that clearly differs from the rest. In those cases it is very difficult to face it and the only thing left to the rest of the companies is to compete based on price. The latter is the worst thing that can happen to an organization. The lack of differentiation makes the product a "commodity"; that is to say, in a generic, basic product, which does not differ from anything and whose only reason for purchase apart from the need for it, is the price. When this happens, the organization gradually bleeds until there is nothing left of it.