[lkrubner]

No one knows why 1973 was the beginning of a long era of economic sluggishness. Oil prices crashed in the 1980s and again in 1990s and again after 2008, but none of these crashes restarted the post-war boom. Adjusting for inflation, oil achieved new lows in the 1990s, and again in recent years, but the very low prices that we see are not enough to bring back the years when the economy grew at 4% on a regular basis. Nothing has revived productivity growth to the 3% a year seen for most of the era 1945-1973. If the spike in oil prices in 1973 was enough to start an era of sluggish growth, then why didn't growth restart once the oil prices collapsed? There are many theories about this, and many brilliant people have written long books trying to explain the events of the last 40 years, but no one knows for sure, and there is nothing like a consensus on the issue, which is why I wrote "No one really knows why."