There are now signs that the local quality of life is starting to improve: overdoses have begun to fall; in the final months of 2023 car break-ins halved. Yet the start of the ai boom predated these changes. Despite headlines about an exodus of the rich, San Francisco’s tech elites mostly weathered the storm—its population decline was, in fact, mostly driven by the exit of poorer folk. As a result, inhabitants are now better paid and more educated than before covid. According to official data, the pre-tax total income of the average working person in San Francisco is around $220,000 a year, compared with $130,000 across the country. ...

Many of the people with the skills to ride the ai wave were already in San Francisco or nearby. Most of today’s tech giants were founded in the suburban neighbourhoods that make up the Valley. Today they, and other big tech firms, have huge campuses 20 or 30 miles south of San Francisco, but their young employees rent cupboard-sized flats in the city. Much of the funding for the ai boom is coming from these tech behemoths. In 2022 and 2023 firms such as Meta completed more Bay Area-based venture-capital investments than ever before, largely focused on ai.

Owing to a mix of government support and creative counterculture, Stanford University and the University of California, Berkeley, have long been centres of ai excellence specifically. In 2017 eight people published a paper, “Attention is all you need”, which recently has become known even outside ai circles as the groundbreaking contribution to the current wave of technological progress. Almost all were based in or near the city. By 2021 San Francisco and nearby San Jose accounted for a quarter of conference papers on the topic, according to the Brookings Metro analysis.

Academic excellence has fed private-sector innovation, with many researchers moving between the two spheres. Nine were hired to build Openai. At first, they laboured in the apartment of Greg Brockman, one of its co-founders, in the Mission District. Data from LinkedIn, a job-search platform, suggest that one in five of Openai’s engineering staff in America attended Berkeley or Stanford. Now San Francisco’s ai concentration has reached a critical mass, with success begetting further success. London and Paris may be ai rivals, but they are a long way behind.