Ancient Israel had landed peoples it also had a priesthood which did not own lands. The general population of Israel lived on the land, the priesthood served in the Temple and when not in the Temple lived with their families in their assigned cities. All Israelites, general landed population and unlanded priesthood lived in the nation of Israel, a nation made by God. A kingdom of God.
So too, the coming kingdom of God. It too will have a population of peoples who will live on the land and those who will serve from time to time in the Temple. Jesus words referred to this arrangement, imo.
In addition, the concrete term (the earth) should not be defined by the lessor concrete term (kingdom of heaven). All the universe can be called the kingdom of heaven, even the planets and stars....but the earth is only one, the earth.
Daytona