I am genuinely worried that the plan of shutting everything down and instituting a quarantine will turn out to be disastrous if it continues for months on end.

The stock market is just the beginning - what about the millions of people making ends meet as waiters, Uber drivers, AirBnb hosts, retail store clerks, and every other in-person job? HN might not feel this much, as the tech industry is making a pretty easy switch to working remotely. But do not be blind to the facts: the overwhelming majority of the workforce doesn't have an emergency fund and won't be able to ride this out easily, if at all.