Taiwan is where we should be looking for inspiration, with South Korea a close second. Taiwan has been manufacturing 20 million masks a day for their citizens, and has been able to contain the pandemic without shutting down their society.
Granted that they have a water border, and were early and aggressive about contact tracing and so on. But the burden is on those who have wacky theories about moral hazard, or who wish to argue from the authority of the WHO, to demonstrate why their specious violation of common sense should apply.
As for the Bay Area, well, they're not the first government to close the barn door after the horses escape. What would things look like if they hadn't listened to the CDC and WHO for as long as they did?
We'll never know, but more like Taiwan is a reasonable guess.
> This wasn't deliberately calculated to kill tens of thousands of people
I haven't seen any data on how much more effective masks are (and which masks) than social distancing. As a sibling pointed out, they might give people a sense of immunity, they might cause people to touch their faces more, etc.
In the Bay Area, they became mandatory-ish after new cases peaked. The only reasons to mandate them at that point is to either get people used to wearing them early or because it makes you feel like you're doing something.