Congratulations on suggesting the most impractical, stupidly dangerous (mmmmh battery fires), impossible to make, single point of failure. At least it won't be attacked because it only lasts a single day anyways.
Stick to philosophy and let actual engineers build a grid, thank you.
San Francisco does not occupy much of the Earth's surface, or even of the continental US. This battery farm, spread out between all the towns in the US, would not even be noticed.
It lasts for a single day. A project using up pretty much all of Earth's currently usable lithium resources, for a single day of storage. It's worthless.
You are really reaching. It wears badly.
I've seen the investment pitches. Nobody is seriously considering it for a reason, it's a terrible, terrible, idea.
Covering intermittent sources is pretty much 100% public sector's responsibility, everywhere.
And, for resources in place, whether so impractical as lithium batteries, or as practical as pumped hydro, iron-air batteries, banked hydrogen, or transmission lines reaching operating generation elsewhere, the space required is in no way prohibitive.
Which was the point.