"Businesses have heretofore demonstrated a preference for early retirement to make way for younger workers," the group observed. "But this preference is a relic from an era of labor surpluses; it will not be sustainable when labor becomes scarce." While enjoying remarkable successes, in short, the United States found itself moving into uncharted economic territory as it ended the 1990s. While many saw a new economic era stretching indefinitely into the future, others were less certain.

Weighing the uncertainties, many assumed a stance of cautious optimism. "Regrettably, history is strewn with visions of such `new eras' that, in the end, have proven to be a mirage," Greenspan noted in 1997. "In short, history counsels caution."