I was thinking about this question, and I don't have a satisfactory answer.

In each of the last "big wars" in Randland (the Trolloc Wars and the Wars after the fall of Hawkwing's Empire) humanity had expanded, they'd almost achieved something like semi-global peace and prosperity. They were filling the map with people and territories.

That's part of why Ishamael started those respective wars... to tear down what they'd built up.

After the Breaking, it took society 1,000 years or so to get to the pinnacle of the 10 Nations. Then BAM, Trolloc hordes invade and tear it all down around their heads. They all fight for a few hundred years, all of the 10 nations are destroyed, and smaller, weaker, less advanced nations replace them.

Another 1,000 years pass, those nations have restored peace and some prosperity, then Hawkwing conquers them all, forging them into a single continental empire, even sending heirs and armies to the rest of the world's landmasses hoping to create a global empire. Again, here the map was covered with countries with no empty gaps of unclaimed lands until Hawkwing forged it into a single empire with provinces. Humanity had expanded again, until Ishy started working on Hawkwing and his potential heirs, destroying their unity and shattering the empire.

In the 1,000 years since then, Humanity on the main continent has not expanded. Small nations have shrunk to simple territories on maps or city states (like Falme, Caralain, Haddon, or Far Madding). Large nations have reduced their borders, and don't even enforce their claim on lands near the edges. The membership of the White Tower is shrinking as well.

Why, in this last 1,000 year cycle, did humanity stop expanding and begin shrinking?

Did humanity stop expanding, or is my central point off base? I'd love to see your thoughts on the question.