The evidence produced is definitely addressing a different argument than the one he actually starts with.

Comparing ancient empires to modern living standards is nonsensical for the purposes of determining if plunder was the basis for empire. And indeed, we know plenty of cases where plunder made wealthy and then ravished entire nations such as the Spanish conquest of Middle America.

His fundamental point is accurate though - there is not a fixed pot of wealth in the world, and the increased wealth of our modern age is due to technology and efficiency, not simply taking things from others.