Where would be the demand for thousands of extra apartments if folk are mostly remote?
There are dozens of cities that have everything else that SF has. If $$ goes away it will crash so hard it will make Detroit look like a model city.
My hope that after election hysteria is over and Vaccines get approved we will be back to something resembling normal by next summer. SF has a huge value as a place for tech with all its other faults it would suck to loose it
And beyond that, people will continue to live in SF just because they want to, not because they have to for their job. Sure, some people will leave because they never really wanted to live here in the first place, but I promise you there are plenty of us who will stay, regardless.