What we learned from the financial crisis — and what we've already forgotten

When calamity strikes - especially avoidable calamity - the human instinct is to look for the silver lining, often by calling the event a "teachable moment."

Consider the most profound economic calamity of the last nine decades, the Great Recession triggered 10 years ago by the collapse of the investment bank Lehman Bros.

The recession suppressed American economic growth so severely that gross domestic product still has not recovered - and might never regain its lost output (by the reckoning of the Federal Reserve Bank of San Francisco). Because of the 2007 housing bust that prefigured the crash, median family finances also have not recovered to pre-crisis levels.

All of this prompts us to ask: What did we learn from this teachable moment? And have we already started to forget its lessons?

The most important teachings to be drawn from the crisis concerned the structural inequalities that had become embedded in the U.S. economy. As Emmanuel Saez of UC Berkeley had shown in collaboration with Thomas Piketty, the top 1 percent of income earners had captured more