[esoterica]

> but you can start on the northwest side and expand it just a couple blocks west, then a few more blocks west.

Again, you are confusing cause and effect. The luxury apartments are popping up because of rising demand and rising prices; they are not the cause the rising prices. San Francisco refuses to build new housing stock and rents are still soaring there because people just bid up the prices of crack shacks.

> The wealthy developers can afford to leave many units empty to maintain the luxury cache of the building or area.

That is completely false. Real estate developers don't intentionally leave a large fraction their buildings empty to project an image of luxury. No renter is going to pay 2x as much rent because they see that the building is half empty and they think that makes it more exclusive. If they wanted an excuse to pay 2x the rent they would just get a larger apartment or move to a more expensive zip code. Deliberately leaving part of a building empty would be an extraordinarily financially dumb move. If a building is substantially empty then the developers screwed up their market research and are losing money on the project.

> Housing supply absolutely needs increased, but we must require developers to build mixed-income housing.

Building luxury housing frees up existing cheaper housing stock for lower income households. You don't have to build cheap housing to make more cheap housing available. Blocking the construction of luxury housing is counter-productive because it just means people will bid up worse housing stock.