I think the other important angle is that land is often the foundation of other property (structures, improvements, etc.) You own land, but care so little about that land that someone else builds some other property on it. Then 20 years later you notice, and try to claim it back, what do you do about the structure and improvements? The adverse possession laws give an incentive to actual owners to exercise their ownership now, rather than incentivizing them to stay silent, so as to later claim the land and all improvements for free.