Answer
The total supply of land is fixed. As a population in civilization increases so can rent prices ; however over time as rent declines there is no change in the amount of land that can be provided therefore there is no incentive. No more land can be added to an economy.
Work Step by Step
To understand this concept think of rent objectively. No matter the changes in price the amount of land is constant and cannot be changed. The supply of land is inelastic.
