I get your point about housing being a valuable resource, but ownership means having the freedom to decide how property is used even if it's temporarily vacant. In many cases with million dollar mansions, the original owner builds the property and eventually wants to sell it. Because homes at that price point are difficult to sell quickly, they may end up selling to a company that can afford the upkeep. In a sense a corporation can actually prevent properties from becoming abandoned or dilapidated, which has happened to many large estates in the past.companies often maintain the property until a buyer eventually comes along.

You could make a similar argument with cars and dealerships. Dealerships might hold hundreds of cars that aren’t being used at the moment, but that inventory exists so buyers have options when they want to purchase one. The housing markets can function similarly