Earlier quoted context omitted.
> Rent is set by supply and demand. There's no law - economic or otherwise - saying that it is necessary for landlords or anybody else to yield a return on capital. Investment opportunities are also a market with supply and demand. The demand for a high risk investment with low expected return is approximately zero. If there are more attractive investment opportunities (higher expected return with lower risk) then mo…
> rental properties must provide a positive return on capital To new investors. GP's point is that the causality is from rent to sale price. In any year any owner (or agent) more or less tries to charge the rent they can get. If this declines, there's nothing an individual owner can do about it. Badly wanting more doesn't open up any new channels to charge more rent (and may even lead you to play your hand sub-optima…
This puts downward pressure on real estate prices in areas which are unprofitable by increasing inventory and decreasing investor demand for rental property.
Market equilibrium will tend to drive prices to the point where units can be profitably rented, and rent will be higher in areas that are depreciating rather than appreciating. This is not a law in the sense of a inviolable law of physics, but I believe it is generally accepted macroeconomic theory.