White flight? Suburbs lose young whites to cities

[RU OX Alum]

So basiaclly, the negative is that it rocks the boat and upsets the status quo and the actual cities become where the rich/er people and poor people will move to the subdivsions? But I don't get how that last part happens, much less is forced. It's not like they evict people in Building A as soon as the rennovate Building B. Is it??