"For all their alleged power, big corporations are often powerless when it comes to the simple task of surviving. As Williamson notes, “Only 67 of the firms in the Fortune 500 in 1955 remained there by 2011.” “The average age of a company listed on the S&P 500 has fallen from almost 60 years old in the 1950s to less than 20 years currently,” a team of Credit Suisse analysts wrote last month. And the death rate is accelerating."