it can also be stupid politics/religion: "your village is the reason for our famine, your entire village is banned from here. you will walk until you see the mountains and until you no longer see them behind you" ... next thing you know, you're in europe or asia.
They where all nomadics, so the concept of a village did not exist yet. It was more like family related moving groups, or maybe "clans". That said, at an individual level there was probably a concept of people exchange when meeting another group, or banning of an individual.
yeah, can replace "village" with "group of people" like families or clans. Basically just 'we blame you for our problems so you need to leave' type of situation.
