If holding back 20% of the units in every building drives up prices by 30% - this is completely possible in something like real estate where supply is so inflex

If holding back 20% of the units in every building drives up prices by 30% - this is completely possible in something like real estate where supply is so inflexible - then each individual landlord might have a motivation to defect, but the group as a whole has a reason to cooperate. The purpose of the software is to give the coordinators visibility into who's cooperating. Note that the TOS requires a landlord to always use the algorithm's pricing decision, including leaving units empty, and requires reporting back on every lease transaction so the company can measure compliance. This really is collusion as a service.