How does the structure of "The Human Drift" influence the effectiveness of its argument?

Jack London’s "The Human Drift" is an expository text whose main argument is expressed in its very first line:

The history of civilisation is a history of wandering, sword in hand, in search of food.

Throughout the story, London builds and supports the main argument using a structure of small paragraphs. He builds a premise and logically arrives at the conclusion. The premises are also interspersed with examples and historical evidence, both from historic and prehistoric times, to strengthen the supporting argument, as shown in the following lines:

From Central Europe the Aryans have drifted into Asia, and from Central Asia the Turanians have drifted across Europe ... The Phoenicians and the Greeks, with unremembered drifts behind them, colonised the Mediterranean. Rome was engulfed in the torrent of Germanic tribes drifting down from the north before a flood of drifting Asiatics. The Angles, Saxons, and Jutes, after having drifted whence no man knows, poured into Britain, and the English have carried this drift on around the world. Retreating before stronger breeds, hungry and voracious, the Eskimo has drifted to the inhospitable polar regions, the Pigmy to the fever-rotten jungles of Africa. And in this day the drift of the races continues, whether it be of Chinese into the Philippines and the Malay Peninsula, of Europeans to the United States or of Americans to the wheat-lands of Manitoba and the Northwest.

The evidence above justifies London’s main argument "The history of civilization is a history of wandering ..." He then introduces his next argument-man is afraid of death-and then he continues to strengthen this argument using the structure of citing examples and tracing man’s journey from the prehistoric to the modern times.