The argument goes like this: high consumer debt, slowing population growth, and rising income inequality have weakened consumer demand and stimulated savings, while slowing growth in productivity and output itself has discouraged investment. So the “natural” rate of interest – the rate at which the demand for investment equals the supply of savings – has fallen, and arguably has become negative.
道理是这样的：消费者债务高企、人口增长下降和不平等的恶化削弱了消费需求、刺激了储蓄，而生产率和产出本身增长放缓抑制了投资。因此，“自然”利率——使投资需求等于储蓄供给的利率——下降了，甚至下降到负水平。但是，由于实际利率不可能处于严重负水平（除非通胀很高，现实并非如此），因此就产生了储蓄过剩。在消费和投资的拖累下，美国经济将注定陷入停滞。