Remember, Christ Jesus rules all of us, and He rules us with a rod of iron, as Revelation states. When nations do bad, and grows sinful, He punishes until the field has been tilled again, and new seeds planted; that's how I view the active kingdom of Heaven. Those in heaven are, in my opinion, responsible for looking over portions of the world. Remember in Revelation, Jesus promised some of the early church that He would give them the "morning star", just as He received from His Father. "Morning Star" is a metaphor of a king, although they may not be the high-king, they are at least responsible for potions of the world, and perhaps even other worlds outside of our solar system, or even our galaxy. This is the one reason why I believe Futurists are wrong in expecting eternity on a small little globe we call earth. The universe is so big and vast that it seems to me that if we are the only ones, then that's an awfully big waste of space [quote from the move Contact]. Now of course, I'm not advocating little green men here.
But I myself believe there are billions of other humanoid planets in other parts of the universe. And sense space is endless, why should we expect pro-creation to have a future end, as the Futurist would suggest? God is so magnificent that our minds cannot even fathom the mysteries, the greatness, and the expanse of His universe. And because we are not even a grain of sand in the universe, I have to believe that procreation and life will always continue, with His Kingdom as the head rule over all the earth; not rule as in authority, but rule as in a guiding light. As our Lord says, we are a light unto the world, set on a tall hill for all to see, so that our light shines upon everyone.