Valuable land is a product of labor, even if only due to being within the boundaries of a secure and orderly society.
Armies, judicial systems, etc, plus labor to bring about the goods and services. Plenty of examples of prime land decreasing in price due to the labor around it not being of sufficient quality/quantity.
It might even be that a society decreasing in wealth (real wealth, in the form of ability to create desirable goods and services) will try to inflate the value of land to preserve the purchasing power of those towards the top of the socioeconomic order.
