memes

There are absolutely scalpers that reduce total supply. They'll only list a couple of consoles that they scalp at a time even if they buy in massive bulk, and it's all done on the pretense of a limited supply from the original seller that they're artificially limiting past what the market would naturally do (by buying a ton of them up). Given a literally infinite supply, scalpers lack an ability to do anything. Put another way, when they can't restrict supply, it's not a viable strategy.

It's not that they refuse to sell some of their supply, it's a temporary restriction (all supply restrictions can be viewed as temporary because we don't have total knowledge of future supply). The temporary restriction benefits them because they can start bidding wars over the reduced supply, and get a higher price per unit at the cost of getting the money over a longer period of time.

The exact same thing works for housing, when you have the same company renting out tons of units but also keeping tons of units in the same area off the market. It means the bidding wars for the smaller supply of units results in more money per unit (lower supply, same demand, means higher costs).

The concept of a prisoners dilemma here only works if houses are fungible, but they're not. There are sometimes very similar units or even houses in a neighborhood in the same location, and these are almost fungible, but even in these contexts those nearly identical units in nearly identical locations are usually owned by a single entity (corporate or otherwise), so again there's no prisoner's dillema, they can restrict supply effectively to increase yield.

The time vs value calculation is different for housing too compared to smaller things like groceries. If you're a grocery store, and your local distributor of apples lowers the price of apples, some of that will likely go to the customer because of local competition pushing prices down, and you have a constant supply tied to a constant demand of these (from a buyer's perspective) essentially fungible things.

Houses are different because if you see the price of houses in your neighborhood drop by some significant amount, individual actors who may otherwise want to sell will actively choose to not list their house because they know the value will go back up, and so these actors are all incentivized to vastly limit supply if something in some area cuts the prices of houses (like a huge influx of new homes for example). These individual actors could be literal individuals or corporations.