Hybrid enables a move from San Francisco to e.g. Petaluma. It doesn't permit most workers to move to Idaho. That argues for an expansion of the Bay Area over its demise.
It's hard to tell what will happen; surely most American companies will leave a main headquarters in the U.S which will probably be hybrid. Than they will have lower cost centers (that will be either remote or hybrid as well).
Overall probably this will push down wages in SV and move it up in places like Germany or Ukraine. But I don't think it will be that dramatic. Salaries will still be very generous in SV.
Hybrid enables a move from San Francisco to e.g. Petaluma. It doesn't permit most workers to move to Idaho. That argues for an expansion of the Bay Area over its demise.