This is the scenario that SPUR is trying to spur, in which private industry and local government work hand in hand to improve the lot for all classes and types of Bay Area residents:
Fast and reliable transit, managed regionwide by a single rail and transit authority, provides the backbone of our transportation system, connecting to the lower-density parts of the region via shared autonomous vehicles, ebikes and new forms of personal transportation. Because we worked to bridge the digital divide, these services are available to everyone.
Our communities are designed to encourage walking and biking. Many neighborhoods have car-free commercial blocks like those found in European cities. Autonomous vehicles and drones deliver some of our goods, but the sidewalks are for people. We welcome new people and new ideas, which has allowed a dynamic economy to prosper.
Over time, some industries have gone away, but new jobs keep emerging as we continue inventing new things. We have eliminated fossil fuels from our homes, vehicles and industries. Innovation in this area generates a significant export industry; we teach other cities and regions around the world how to build high-performance energy and transportation systems, the same way the Dutch export their water management expertise.
It's hard to imagine this scenario happening, given how little progress has been made on problems such as rampant homelessness in the last several decades, but that's the point of the paper -- if we don't consciously make decisions today with 2070 in mind, the future won't look the way we want it to.
It's well worth a read, especially given that the Bay Area faces more extreme versions of national problems like income inequality, and has proven to be a bellwether for the rest of the U.S. many times in the past.