In the period leading up to the 2008 Global Financial Crisis, a few prescient voices warned of potentially catastrophic systemic instability. In a famous 2005 speech, Raghuram Rajan explicitly cautioned that although structural and technological changes meant that the financial system was theoretically diversifying risk better than ever before, it might in practice be concentrating risk. At the time, Rajan was mocked. Former US Treasury Secretary Larry Summers was not alone in thinking him a “Luddite”.

This episode comes to mind because of the widespread shortages emerging around the world. M...