Let's not forget that economists (and to a larger extent, people in general) are notoriously terrible at predicting the future-- even the near future, let alone

Let's not forget that economists (and to a larger extent, people in general) are notoriously terrible at predicting the future-- even the near future, let alone what might happen in 20 or 50 or 100 years. The economy is just too complex. Where economists excel is analyzing and explaining what happened in the past.