Brooklyn and Queens didn't become dense residential areas with relatively painless commutes from the city overnight. It's not like there isn't land for such areas in the bay area, the biggest issue is that they are all separate cities and have separate local governments.

Well, all we need to do is make Oakland seven times more populous, and it's Brooklyn.

And more accessible by transit. The parts of Oakland near BART are super easy to get to FIDI, Market, the Mission, etc, but huge swaths of the Town are miles from BART.

Hell, drop a few BART stations in Alameda you'd be a huge step in the right direction.

The population of Oakland is more densely packed around BART stations than is the population of San Francisco. Yes there are “large swaths” within the city limits, but they are the least populous.

Some Second Transbay Tube plans mention a stop in Alameda before entering Oakland.

Whether the project happens in San Francisco's lip-service to transit NIMBY climate is the bigger question.