Such city states can handle all the issues normal to such communities including title for living space easily handled in our world of condominiums. Much more critical all lands surrounding such States can be managed through a polity called a communion of states and whose principle concern would be land sustainability.
In this manner, land husbandry is separated from land ownership. Modernity makes this completely possible. I would expect all lands to ultimately be directly managed by natural comminuities availing themselves of both modernity and an internal economy properly using internal fiat currency methodologies as well.
The massive land based state as we now know it would simply cease to be important at all and would express itself as an expanding corporation exploring space and employing and moving talent..