I recommend a fascinating piece of academic research whose title is the headline above. It’s by Edward Glaeser and Giacomo Ponzetto, both of Harvard. They argue that advances in communications and transportation technology over the past few decades had two contradictory effects on cities, one negative and one positive. On one hand, better communications hurt cities (which are marked by extreme density) by reducing the importance of proximity for shipping goods and exchanging ideas. On the other hand, better communications can make new ideas more valuable by allowing them to be spread and used around the world. That, in turn, would make the hatcheries of new ideas more valuable.
So, which effect predominates? It depends. Glaeser and Ponzetto argue that for goods-producing cities like Detroit (right) and Cleveland, the negative effects have dominated, but for idea-producing cities like New York (left), Boston, San Francisco, and Minneapolis, the positive effects have dominated.