Why did some cultures spread and others shrink? There is no single “best” blueprint. Expansion often rewards adaptability more than virtue, intelligence, or strength.
Flexibility becomes a quiet advantage. Humans can coordinate around shared myths, rewrite institutions, and absorb foreign practices. Empires and religions spread not only by force, but by copying what works: crops, scripts, technologies, and administrative habits.
History then looks less like a contest of pure civilizations and more like a traffic of borrowed tools. Societies steal, remix, and later call the mixture “tradition.” Winners absorb features from the conquered, and the conquered adopt features from the winners, so boundaries blur.
The secret is not purity. It is changing fast without losing cooperation. A society that cannot bend breaks. A society that bends without limits dissolves.