In 2005, a control room for the A and C subway lines in NYC caught fire. "No larger than a kitchen," the room held 600 relays, switches and circuits that keep track of trains and keep everything running. Officials originally thought it would take three to five years to get the lines back to normal capacity. (Thankfully it didn't.) The epic repair time was because the fixed-block signaling system dates back to 1904 and only two companies in the world were able to repair it, one in Pittsburgh and the other in Paris. This is technology's trailing edge, according to Peter Sandborn in IEEE Spectrum: the huge, crippling problem of obsolescence.
Three percent of all the electronic components in the world become obsolete every month. When you imagine all the shit coming out of China, it's pretty staggering. The problem is actually worse for the military, which spends about $10 billion a year on keeping up obsolete electronics parts. Ironically it's because they've switched to using off-the-shelf consumer electronics for 90 percent of their components—with a much shorter service life, four years at best—rather than "military-spec" gear, which was designed to hang around for a decade or more.