Investors are traumatised by the decade-long boom-and-bust cycle in which shale-drillers burned through more than $150bn in cumulative free cashflow from 2011 to 2020.

长达 10 年的繁荣与萧条周期给投资者带来了创伤，页岩钻探公司从 2011 年到 2020 年消耗了超过 1500 亿美元的累计自由现金流。

Profits have, it is true, been higher in America since the financial crisis of 2007-09 than in previous decades, especially if you consider free cashflows, which account for the changing way companies depreciate assets (see chart 3).

的确，自2007-09年金融危机以来， 美国的利润一直高于前几十年，特别是如果你考虑自由现金流，这是公司折旧资产方式变化的原因（见图3）。