America prides itself of allowing its denizens to move from place to place, from town to town, from city to city, from State to State, so that, just becauseyou currently live in a safe neighborhood, or a decent neighborhood, or an okay neighborhood, or a great neighborhood, doesn't necessarily mean it will always be that way, as though, in theory, things always get better, because there are certain specific neighborhoods in which things don't ever seem to get better, rather, they inevitably get worse, and sometimes a lot worse.
For instance, whether it is labeled correctly "white flight" or not, when a given neighborhood for whatever reason has a traumatic change in its perspective, or demographics, or work force, the cascade of changes affecting such a neighborhood can have an enormous impact upon those that are left behind. That is to say, neighborhoods that have more money, neighborhoods that have more income, neighborhoods that have more wealth, neighborhoods that have more net worth, are typically going to be neighborhoods that have a surrounding infrastructure that supports that material fact, so that the parks will be better and safer, the policing of such will be more professional and competent, the schools will be better, the infrastructure of stores, shops, libraries, hospitals, roads, and so on and so forth, all will also be better. This signifies for those neighborhoods, that living in such a community will be pleasant, for it is, by definition, a nice place to live. On the other hand, when all these things are going in the opposite direction, the very opposite thing will happen, which means that the neighborhood and all the peripheral things that go with being in a safe and nice neighborhood, will be appreciably worse and trending strongly to that downward spiral.
This means, when, for whatever reason, there is a perception that the racial mix of a neighborhood is considered to be trending towards intolerable, or the religion of new residents is suspect, or the look and behavior of residents seems uncivil or uncomfortable, or there has been a notable closure of a means of employment, or the infrastructure of public places is suffering from disrepair, that those that are most perceptive, or perhaps more correctly considered most selfish, will, if they have the means and wherewithal, begin to plot their escape and removal from their current living situation into a neighborhood that they find more suitable. This would be okay, except for this very important reason, which is, if the neighbors that first leave a neighborhood which appears to be on the downswing, are those neighbors that have the most money, that have the most wealth, that have the most education, that have the most means to move out and they do indeed move out, than the residents that are left behind are in aggregate, less of all of these material things, making the neighborhood not only appreciably poorer but also far more vulnerable to dire consequences.
In America, it seems far too often, that is always easier to build something new or to start anew, rather than take what is already in place and to thereby take the necessary steps to fix it, or to repair such, before it becomes too late to mend it or to replace it. Communities in which the economic opportunities have been eviscerated, in which the school system has become second-rate or even worse, in which the policing is seen as the problem and not as a service, and the residents have devolved into apathy, or incivility, and fear and discord are part and parcel of such a community, aren't going to be communities of people that are good neighbors, but instead are going to be communities of neighbors that have become an underclass which is under-served, under-cared for, and left behind as the losers in a game that they didn't even know was being played.