Can we think of a scenario like this: Lots of land, but a whole lot less people? If this happened after the collapse of Rome, when else might it happen?
I think a palomino would make a very nice Cossack horse.
As a post script, DeLong answers the questions as to why Serfdom has not reasserted itself in the modern world:
Why hasn't bound labor reemerged in the modern world? Elites in developing countries can no longer be confident in their ability to earn hefty incomes by employing workers and paying them much less than their average product: an elite monopoly of land ownership is no longer worth much. So why haven't they responded to the potential erosion of their collective economic edge by turning to politics and force to bind workers?
One answer is that, to some extent, they have: Consider that modern states are surprisingly effective as tax-collection machines, and in large chunks of the world the elite's power and (relative) prosperity is rooted in its "new class" control over the flow of resources from the state. Consider, also, the Communist Party of Vietnam--what is it but a gang labor boss for unfree labor deployed to produce shoes for Nike? Brad DeLong, The Causes of Slavery or Serfdom: A Hypothesis, May 10, 2003.
Which is probably why some people seem to be awfully impatient for the apocalypse to hurry up and get here already!