Many people will be born, have kids, and die in one region and culture. Only recently in human existence have some people been afforded such easy movement. 500 years ago, it would have been basically unthinkable that you could leave your family and go start a life on the antipode of your birth location in exchange for maybe a few months wages. Most of humanity had to work just to survive... agrarian society wasn't THAT long ago even in developed nations. Cultural mores are real and, especially when it came to who gets your daughter, VERY long lasting traditions and rules.
You are viewing this discussion through the lens of your own modern reality. That is dumb, not insightful.