"In 2022, San Marino’s City Council proposed a ballot measure to levy a $10,000 tax on vacant commercial and residential properties, but it ultimately failed to pass. "

Considering the values of some of this housing, that's probably not enough to force units back onto the market.

https://archive.md/ARWaq

Major policy failure on the part of Dems (and the YIMBYS who advocated building all of the luxury condos that fed this market).