" The Fortune 500 list of 2011 featured only sixty-seven companies that appeared on the list of 1955, meaning that just 13.4 percent of the Fortune 500 firms in 1955 were still on the list fifty-six years later. Eighty-seven percent of the companies simply couldn’t keep up; they had either gone bankrupt, merged with other companies, been forced to go private, or fallen off the list completely. "

― Stanley McChrystal , Team of Teams: New Rules of Engagement for a Complex World