>the highest per capita infections (both total and current) were mostly in rural, not metropolitan, counties.
Can you please cite your sources for this claim? I just did the math using the numbers of infections[0] and the county populations[1] and it doesn't really seem to match up with your claim at all.
There are 58 counties in California.
San Bernardino, LA, and Riverside counties are numbers 4, 5, 6 respectively for highest cases per capita and all have populations above 2.2 million.
Of the bottom 10 counties in cases per capita, only 2 have a population larger than 100k (SF, Humboldt)
[0] https://usafacts.org/visualizations/coronavirus-covid-19-spr...