This really all comes down to a monopolization problem. Even back when the human population was small, a king would own everything and put people in jail for hunting deer on his land. This is why humans always explore and go out into new areas, to try and get a claim on something.
When the world runs out of places for people to do so, you then live in a prison. At that point, I can't think of any logical solutions besides the population going down until the entire surface of the planet can't be monopolized, otherwise, groups in certain nations would likely join for collective benefit to go to war and expand.