[randomgermanguy]

Yes, but in practice land-ownership is only zero sum in places like Europe where every square-kilometer has 300 years of documented ownership etc, or other high-density areas.

The Asia, Africa & the Americas have so much unused space that isn't as inhospitable as central Australia

[graemep]

Where in Asia do you have in mind? A few things I know off hand. Sri Lanka has a higher population density than Britain, Japan's is much higher than that, and Java has nearly the population of Russia in an area smaller than England (just England, not Britain or the UK). India and China are big, but have huge populations.

There is lots of "unused space" in places like Alaska or Siberia or deserts or mountains, but land is not a fungible commodity. Unused space is unused for a reason. In practice, almost all ownership of land is a zero sum game.