In my mind, the situation is so drastic because (I would expect) the massive population flight will have long-term negative implications for the tax base, which

In my mind, the situation is so drastic because (I would expect) the massive population flight will have long-term negative implications for the tax base, which means less money for social programs and upkeep of city infrastructure. Judging by the lack of sanitation in many of the city's neighborhoods, my uninformed guess is that there was already a lack of such funds before COVID hit. The impact of this flight on the tax base could be even more severe if the people leaving are higher-than-average earners (which, given their mobility, my guess is they are). Moving to a new city is a non-trivial life change, and once people move, they're unlikely to move back anytime soon. At the risk of sounding melodramatic, I can't help but wonder if we'll be comparing San Francisco with Detroit in 5 years. I hope I'm wrong.