He didn't say anything about making it more valuable, just that it would increase liquidity. In other words, the idea would be to prevent property from sitting

He didn't say anything about making it more valuable, just that it would increase liquidity. In other words, the idea would be to prevent property from sitting dormant in a bad market, as an owner who has no profitable use for the property would be forced to sell it to someone who does, to get at least some value out of it before the tax eats all the value. Perhaps something like an abandonment tax could accomplish this. Force owners to either sell it or use it. Even if they aren't using it optimally, just requiring some minimum usage to avoid a heavy penalty tax could go a long way to eliminating properties that are just tied up by someone hoping the value goes up eventually.