Moats, Bottlenecks, Picks, and Shovels: the "fundamentals" you invest in aren't forever

Here's a list of companies that at one time were considered to have an undisputed and unassailable moat. It was assumed that these were absolute rock-solid safe investments that could do nothing except grow in perpetuity: Xerox, Cisco, Worldcom, Kodak, Sears Roebuck, US Cotton, Bethlehem Steel, Nortel, Blockbuster, Nokia, Polaroid, Compaq, Borders Group, Lehman Brothers, Washington Mutual, Pan Am, Chicago Gas, Pullman, Ford, Bear Stearns, Lincoln Savings and Loan, BCCI, Motorola, Singer, General