[mamon]

Upper middle class are usually not homeless, right now they occupy some pool of apartments in cities anyway. By building more luxury apartments you encourage them to move, thus leaving their old apartment behind, either by putting it on sale, or renting it out.

Think of this like a domino effect: those earning $10M per year buy luxury residence, leaving their old house for those earning $1M, who in turn leave their own houses to those earning $500K, who leave their apartments for those earning $200k, and so on, and so on.

In the end everybody benefits from new housing being built, even if it's only luxury housing.

Also, increasing supply keeps prices down, thus decreasing profitability of buying houses as investment, causing larger share of apartments to be bought by people who actually plan to live in them.

EDIT: yes, this effect might not work as described if is limited to just one city, because there might be a lot of people wanting to move from elswhere. Or more precisely: it will work, eventually, but it would require much more housing to be built to meet the demand.

[wander_homer]

> Think of this like a domino effect: those earning $10M per year buy luxury residence, leaving their old house for those earning $1M, who in turn leave their own houses to those earning $500K, who leave their apartments for those earning $200k, and so on, and so on.

This assumes that a) rents don't increase for the new residents (which is false) and b) people only move within a city and there's no high demand from people outside to move into the city (which is false too).

[kaybe]

I don't think they're going to move that easily. Rent has been going so much it is eating a larger income share than before for many of them too.

So what that leaves you with is disproportionate increase of demand and prices for smaller cheaper units.

[jdreyfuss]

Yes, this fits closer to reality. Most people want to spend as little as possible on rent for a situation that matches their needs. Just because fancier apartments become available at higher prices doesn't mean people will move into them from a cheaper place just because they can technically afford it. Plenty of people rent apartments below their "I can afford this" level in order to use that money elsewhere or save up for a future house.

Building luxury housing doesn't push prices lower on the bottom half of the housing spectrum, it just makes the top end higher. "Trickle down" housing takes way too long to be realized, while subsidized housing has a much stronger and immediate impact[0]

[0]https://www.urbandisplacement.org/sites/default/files/images...