In her book The Economy of Cities, the great urban theorist Jane Jacobs praised what she called the “valuable inefficiencies and impracticalities of cities.” To explain her point, she invited readers to consider two examples from 19th century England: Manchester and Birmingham — or as she put it, “Efficient Manchester” and “Inefficient Birmingham.”

As I have written before, efficient Manchester specialized in textiles, building a world-beating industry dominated by a few large, streamlined companies. Inefficient Birmingham, by contrast, housed dozens of different trades. And in place of a few big companies, most of Birmingham’s manufacturing was performed by small organizations employing a dozen or fewer workmen, Jacob writes.

At the time, everyone from free-market economists to Marx himself saw Manchester as the “city of the future” and Birmingham as an obsolete backwater. But reality took a different course. Manchester’s textile industry quickly peaked and collapsed, pressured by lower-cost production in colonial India. The city entered a long economic depression, from which it only emerged after World War II. Meanwhile, Birmingham’s economy grew steadily over the decades and remains robust today.

To me, Jacobs’ Manchester/Birmingham discussion provides a kind of über-fable for city planning and development. Among its lessons: cities shouldn’t specialize in a single product; beware dominant, streamlined enterprises; and nurture small, interdependent businesses that tend to spawn new enterprises rather than swallow up existing ones.

Food production seems to me to represent a classic Birminghamian set of activities. It sounds like a single thing, but really it contains a multitude. People eat every day, and they like variety. That means a potentially steady market for a wide range of products. And increasingly in U.S. cities, people like to eat really good stuff made by small-scale artisans with whom they can communicate directly. Restaurants have always served that function to a degree, but there are infinite possibilities outside of the restaurant, with its crushing startup and operational costs.