十五年前，美国正处于所谓的“期望贬值”时代：生产力增长停滞；能源价格高昂；经济大萧条时期被积压的潜能技术已经枯竭；规模经济导致的收益渐亏使得几乎每一位经济学家做出这样的预测：经济增长速度在未来将远远落后于过去。
Fifteen years ago, the United States was in the midst of what you could call its “Age of Diminished Expectations.” Productivity gains had stalled, energy prices were high, the backlog of potential technologies that originated in the Great Depression had been exhausted, and waning benefits from economies of scale led nearly every economist to project that economic growth would be slower in the future than it had been in the past.