You tax all the rent they earn due to holding the land [0], since all the reasons rent is high in SF are not due to contributions by the landowner (ie. the comm

You tax all the rent they earn due to holding the land [0], since all the reasons rent is high in SF are not due to contributions by the landowner (ie. the community put in effort to make SF desirable, yet the landowner gets all that value). See https://en.wikipedia.org/wiki/Land_value_tax https://en.wikipedia.org/wiki/Land_value_tax and https://en.wikipedia.org/wiki/Georgism https://en.wikipedia.org/wiki/Georgism [0] - But let them keep all the rent from the building, since they built it with their own capital and labour.