people were moving because they were exhausting natural resources (not because they didnt know about agriculture or how to settle). when resources were abudant (or their tribe was small) they didnt move. agriculture or stock breeding or hunting or any other food technology doesnt imply settled or nomadic life style. there were moving agricultural cultures. they used to settle for a major period of time (decades) and then abandoned their village and moved to a new place (where they started to work a fresh, fertile soil). on the other hand, there were permanent settlements of hunters or fishers, and they exist nowdays among some primitive cultures.
even when you settle in the game you can still imagine that you are nomadic: as a city works a number of surrounding plots, you can think of your cultural borders as of a territory of your tribe, where your "citizens" (tribesmen) roam gathering resources.
what can be done - abandon a city interface command introduced, that way your city is destroyed and you get a settler on its plot. when you settle in another place, new city starts with a population of the abandoned one. that way you could settle at the first turn, build a scout, then build worker while your scout is scouting, then abandon that city and move to a better location.