Why do Big, Well-Established Firms Fail?

You have nearing the end of your MBA program and have read a lot about the competitive environment in which firms function; the various functions of business and tools associated with those functions; and thinking critically and strategically. That reading included theories on harnessing the organization's resources to neutralize threats it faces, exploit opportunities in an effort to create competitive advantage. You have studied and even applied, presumably, powerful tools and models like VRIO, Porter's models, SWOT, TOWs etc.

Organizations are run by people who have had the same experience and education you have had. And, yet, they fail, sometimes after having been an immovable force in their industries for a hundred years or more. Maybe, this seems like an unfair question, ranking alongside "why do people die when we have so much medical knowledge," but I am asking, "Why do firms fail? What is the value in the theories you are studying?"