As we wrote two days ago, the DrsC are more likely to experience contagion when traveling by plane or cruise ship - close quarters being the operational mechanism. When we travel in our private vehicle or stay home, the odds are much more in our favor.
Very simply, the issue is how tightly we are packed in with others. Public transportation is a serious contagion risk factor.
Victor Davis Hanson writes in National Review about the relative lack of Covid-19 cases and fatalities in California. He develops a conspiracy theory of his own, arguing the Golden State may have gotten (and gotten over) coronavirus last fall and developed a "herd immunity." Perhaps he is correct.
Occam's razor suggests a simpler answer; relatively few Californians utilize public transport on a daily basis. Metro San Francisco is virtually the only place in CA where doing so is even feasible for most people.
The DrsC had two elderly aunts who lived in SF their whole lives and never learned to drive a car. Among Californians this made them near-unicorns, real oddities.
As native Californians, we've joked that to be born here is to pop out with an ignition key in your hand. Driving is our birthright. As we grew up the important milestone in one's life was not voting age or alcohol purchase age, but age 16, when one got a driver's license.
We hear this is less true today, but Californians are still a people on wheels. Few CA cars have more than 2 occupants, and many are solos. Natural social distancing - it has to have positive health consequences, compared to strap hanging on a crowded subway car or bus, contributing to the shared miasma.