What about the NIMBYs?
Despite being a major tech hub, San Francisco itself presents a challenge for companies who would run fiber lines in the hilly terrain, unique architecture, and densely-packed clusters of houses and apartments in many of the city's neighborhoods, where ripping up copper wiring and installing new lines can be a painful and costly endeavor.
The NIMBYs and the horribly inefficient government have more say into why it’s so hard to build fiber in San Francisco. And anything else, really. Since so many techies are immigrants and cannot vote, the burden falls more strongly on native San Franciscan techies to change this state of affairs.
Monkeybrains tried to do micro-trench fiber, but apparently never discovered the necessary paperwork.
Google tried to do a fiber and WiFi thing with the previous mayor, now lieutenant governor, but the dysfunctional Board of Supervisors shut it down.
AT&T tried to do a FTTN deal, fiber + DSL, but the NIMBYs complained and shut it down.
In addition, there is no coordination about what happens when the streets are torn up, so every sewer, gas, and water project tears up the streets again and again and leaves the roads all lumpy. If they would install fiber and conduits when they fix other stuff, that would make Internet access more affordable.