> OK, so the answer to my question is “No”.

So what? Something which hasn't been done yet must not be attempted? Or is it doomed to fail?

The transition of many electrical systems is a work-in-progress. A complete re-haul of such heavy industry branch cannot be quickly completed, especially during a global crisis.

> You can safely ignore all the households, they barely use any power compared to commercial and industrial facilities.

Nope.

USA: Residential customers (139.894 million) directly consumed 1,509.23 TWh, or 35.23% of the total.

Source: https://en.wikipedia.org/wiki/Electricity_sector_of_the_Unit...

> What is the office tower going to do, use backup batteries from 500 cars in the basement to run dozens of pumps and fans?

A continental mix of renewables can cope most of the time. The point is the 'backup' (when a geographical zone doesn't produce enough and cannot be helped by another zone): dams, batteries, green hydrogen...

> Supplying 30% of California’s power is not 100% backup of the grid with batteries

This is a work-in-progress. 15 years ago some said that renewables will never be able to generate more than a few percent of the current running on national grid.

> We are a ridiculously long ways away from an exclusively solar + wind + batteries grid.

To each is own opinion.

Production trend: https://ourworldindata.org/grapher/electricity-fossil-renewa...