not enough to house significant influx from urban areas without become one itself

Well yeah it's a tautology that you can't have a significant number of people with 90 %ile schools for example. Fortunately, it seems that a decent number of people like the above poster consider such areas to be "hell", lots of people can't work remote, and the general sense I've gotten is that the nice areas that are more attainable for the upper middle class (high six figure-low seven figure as opposed to mid seven figure homes) tend to be in red states, which acts as a repellent for a lot of the would-be competition.