[2006alum]

I wonder how many New York’s were avoided?  

It’s not clear to me why other than SIP San Francisco, the country’s second densest city, avoided the events that played out in New York, the country’s densest city.

Because millions of people don't commute through San Francisco via cramped, overcrowded subway cars:

Bay Area Rapid Transit (BART) is a rapid transit public transportation system serving the San Francisco Bay Area in California.
Overview
Daily ridership
411,000 weekdays 161,000 Saturdays 116,000 Sundays (FY 2019 average)

Overview of the New York City's transit system
The subway has a daily ridership of approximately 5.5 million and an annual ridership in 2019 of roughly 1.698 billion. Our system includes: More than 6,600 subway cars, which collectively traveled about 365 million miles in 2019. 472 subway stations.

As a recently relocated NYCer, I continue to believe that the inability to create a socially distancing daily commute for many NYers will be the single biggest obstacle to get back to normal. There is simply no way to effectively enforce social distancing measures on the subway. Even stopping people to check that they are wearing masks before boarding would stretch the system's personnel. And the MTA is linked up to New Jersey Transit, Metro North (which services NY and CT bedroom communities), and the Long Island Railroad, which is in part why I think parts of CT and NJ were hit nearly as hard as NYC.

[2006alum]

I wonder how many New York’s were avoided?  

It’s not clear to me why other than SIP San Francisco, the country’s second densest city, avoided the events that played out in New York, the country’s densest city.

Because millions of people don't commute through San Francisco via cramped, overcrowded subway cars:

Bay Area Rapid Transit (BART) is a rapid transit public transportation system serving the San Francisco Bay Area in California.
Overview
Daily ridership
411,000 weekdays 161,000 Saturdays 116,000 Sundays (FY 2019 average)

Overview of the New York City's transit system
The subway has a daily ridership of approximately 5.5 million and an annual ridership in 2019 of roughly 1.698 billion. Our system includes: More than 6,600 subway cars, which collectively traveled about 365 million miles in 2019. 472 subway stations.

As a recently relocated NYCer, I continue to believe that the inability to create a socially distancing daily commute for many NYers will be the single biggest obstacle to get back to normal. There is simply no way to effectively enforce social distancing measures on the subway. Even stopping people to check that they are wearing masks before boarding would stretch the system's personnel. And the MTA is linked up to New Jersey Transit, Metro North (which services NY and CT bedroom communities), and the Long Island Railroad, which is in part why I think parts of CT and NJ were hit nearly as hard as NYC.