"Stadtliche luft macht man frei" is an old German saying. City air makes you free. Life in a small town can be stifling. That close-knit family wants you to be just like them. God forbid you want to do or see anything new. The moving-to-a-big-city trope is as old as cinema, and has strong roots in reality.
In the middle-ages in at least in what is now Estonia, if you ecaped to the city and lived there for a year and a day you would be set free from your serfdom. "Linna õhk teeb vabaks" same frase was used for that.
There were free peasants outside cities. The specific reason is a serf could run away to a city, and if he managed to stay long enough, he stopped being a serf and became a citizen.