SYDNEY, Australia — Down the hill from my house, there is an old building with a saw-toothed roof that once warehoused trams, back when the bay was heavy with industrial waste and working-class people could afford to buy a home this close to the city and harbor of Sydney.

Now that building has been revived and repurposed as a dining destination for our perfect little inner-city neighborhood at Glebe Point. The graffiti that marked its derelict years have been retained — except for offensive words, which have been scrubbed out. A bakery mills its flour right there before you. A restaurant serves produce from farmers known to the chef. It is “local and authentic,” the kind of local and authentic that deserves scare quotes because it is just as likely to be found in Williamsburg, Brooklyn, or the Shoreditch neighborhood in London.

The work of the urban theorist and activist Jane Jacobs is the subject of public discussion again, with the recent publication of a biography about her, “Eyes on the Street.” Ms. Jacobs is credited with helping save her New York neighborhood, Greenwich Village, from the threat of an expressway. Through her books, such as the seminal 1961 work “The Death and Life of Great American Cities,” she championed the diverse and dynamic urban neighborhood — sidewalks busy with foot traffic rather than automobiles and ripe for chance interactions; the friendly chaos of old and new, home and work, all within the same few blocks — seeding ideas that have been taken up in other cities around the world.

Yet for all its worth and triumph, at some point in the last 20 years, this dream died and became something else. Those urban villages, once diverse melting pots, became shiny, wealthy and inward-looking. The big ideas became small and hard and sparkling as diamonds.