What happened in San Francisco during the pandemic 2020/21? What is the future of Silicon Valley & California in the era of climate change.

California, the biggest economy in the USA, the 5th economy in the world, with Silicon Valley as innovation cradle. One of the most progressive states in the USA, the first state to introduce a full lockdown in March 2020. 
What happened in SF and in the Bay Area during the pandemic was unique but also understandable. SF become a ghost town. Several flagship companies such as HP or Oracle have moved out, also many key figures declared to move - like Elon Musk, as well as many employees.
Is it an exodus from Silicon Valley?
The pandemic has accelerated the process of moving out. But it wasn't the only reason many left.
Why are they leaving? 
San Francisco is one of the most expensive cities in the USA. Remote work created new possibilities for working from almost anywhere. 
Due to wild fires (related to climate change) San Francisco becomes one of the most polluted cities in the world. It’s also a city of contrasts - ultra-wealthy IT celebrities vs homelessness crisis.
The post-pandemic Silicon Valley is likely to spread beyond its geographical boundaries. Who will win the talent pool? Is teamwork and innovation able to grow in the era of remote work? 
New Technologies for the Planet: Will Silicon Valley's technological thought and its capital help stop the climate catastrophe?