You're assuming they were the first kind of fools rather than the second kind.

> Leaving units unsold to maintain agreed-upon price floor despite insufficient demand: collusion, market manipulation. Congratulations, you are a cartel.

Which is the thing that doesn't work when many other landlords aren't in on it, because then they get to fill their vacancies while you're stuck with the empty units.

Notice also that antitrust prohibits attempts to monopolize. Fools are quite capable of doing something which is still a violation of antitrust laws despite being ineffective and unprofitable.

Almost always.

The trick is figuring out where the failure is coming from, and whether your society can find a lever to pull to fix it.

In general the homeowners are more numerous but the landlords are somewhat more organized.

The homeowners are also being taken for a ride, because less restrictive zoning reduces the value of units (since you can increase the supply of them) while increasing the value of each piece of land (since you can now build more units on it). And the homeowners (and small landlords) are typically the ones with a high ratio of land to units, but they get hornswoggled into demanding the thing that really benefits the corporate landlords who own the existing high density buildings.

I’m speculating the price would be closer to $1,400 per unit.

The price across this hypothetical town is $2,400 per unit (let’s say it’s a 2 bed 2 bath apartment), “suggested”/set by RealPage software.

Because that’s how using their product worked.

Half of them sit empty because their business model doesn’t care (tax deductions on other income, while still increasing total assets in their portfolio).

There is…a good amount of evidence of landlords doing this, and how:

https://www.justice.gov/opa/pr/justice-department-requires-r...

and

these landlords coordinated through a variety of means, including:

Directly communicating with competitors’ senior managers about rents, occupancy, and other competitively sensitive topics. In one example, Greystar supplied Camden with information not only about very recent renewal rates, but also its approach to pricing for the upcoming quarter, its acceptance of RealPage’s pricing recommendations, use of concessions and competitively sensitive information about occupancy. Likewise, executives at Camden and LivCor communicated over the course of months about their pricing strategies, including plans for certain price increases. Regularly conducting “call arounds.” During these discussions, euphemistically referred to as “market surveys,” property managers called or emailed competitors to share, and sometimes discuss, competitively sensitive information about rents, occupancy, pricing strategies and discounts. Participating in “user groups” hosted by RealPage. For instance, landlords discussed via user groups how to modify the software’s pricing methodology, as well as their own pricing strategies. In one example, LivCor and Willow Bridge executives participated in a user group discussion of plans for renewal increases, concessions and acceptance rates of RealPage rent recommendations. Sharing information with competitors about parameters in RealPage’s software. As an example, at the request of Willow Bridge’s director of revenue management, Greystar’s director of revenue management supplied its standard auto-accept parameters for RealPage’s software, including the daily and weekly limits and the days of the week for which Greystar used “auto-accept.”

Not everything is "Economics 101."