I'm not sure what you're saying here: the value of a commodity is measured by the probability distribution of being able to buy that commodity for a given price. If it's hard to find a unit to rent at price $X, that's the same thing as units being more expensive than $X. Imagine paying an agent to watch MLS and leap on offers for you, or paying other people to temporarily leave the market, or just spending your work-hours at home on the phone to realtors, etc. The inefficiency of those things is, itself, part of the cost of the unit.