"Trickle-down housing" is a term invented solely to attack the YIMBY case and conflates two unrelated things: "supply-side economics"--which is itself misnamed, because it is actually sending money to meet the demand-side of rich people, which was derided by its opponents as "trickle down"; as in, the money eventually trickles down to everyone else-and "filtering", which is the general observation that older housing becomes less valuable and thus more affordable, all else being equal.

Filtering is now derided by YIMBY opponents as "trickle-down housing", because the YIMBY point is that new "luxury" (a marketing term with no descriptive value other than "market-rate") housing will make older housing more affordable than it would be if that new luxury housing was not built. But on the scale of a city, this only can happen if the density of the new development is greater than before.

In the context of this original article, California did a great job in destroying cities with Proposition 13 which allowed homeowners and their inheritors to become incredibly rich and pay no taxes for massively increased land values, freeing them up to fight anything they didn't like forever with no negative consequences, while renters got screwed. They had to be screwed, not just because of a lack of rent control, but also because any new building of any sort has to pay fair taxes.

In fact the "fair taxes" aren't fair, because buildings reset to market rate taxation, because they are newly built or because they are substantially modified, have to pay for all the undertaxed old buildings. This fact doesn't directly account for high overall housing costs- zoning, punitive "impact fees" on new development, and other policies do that- but it does mean that any new unsubsidized development has to charge high rents to pencil out.

So the "greedy landlords"--and they are greedy, it's capitalism-- are subsidizing the righteous homeowners who stood against overdevelopment. Well, at least the ones who own newer buildings do.

It is now too late and California is hemorrhaging population thanks to their intransigence, so California has passed YIMBY laws to fix the problem over their objections. Reality has shown one of the premises of this article--the idea that developers want to build in low income neighborhoods because land is cheap--to be false. Quite the opposite: developers have filed builders remedy complaints in Huntington Beach, Santa Monica, and other relatively wealthy towns. This is what YIMBYs thought would happen, because we understand that land is a residual and paying more, for more expensive land, one time, is only a small part of a development that can command higher rents.

All the other stuff about governments needing to "build affordable housing" or evil corporate landlords charging high rents is a smokescreen. These corporate landlords do not want more housing to be built and they say so in their corporate disclosures! It is a material risk to their bottom lines. Avalon Bay, Kushner, etc do not want competition. As for government needing to build affordable housing, who pays for that? The response is usually, "the rich". And how are they to be taxed exactly? The city can only tax them if they live here. And where are they going to live? Either they live in new "luxury" apartments, or they live in existing mansions, or they buy a crappy old house and demolish it, often demolishing multifamily housing for one big house, which is what they're definitely going to do if you make building new "luxury" buildings impossible.