In order to live in those cities you do need a household income of $200K+. But that is not middle class. In such cities the statistical middle class would be $5

In order to live in those cities you do need a household income of $200K+. But that is not middle class. In such cities the statistical middle class would be $50-75K, but as a percentage of the population it would be a small (and increasingly smaller) group... Which is the crux of the problem. Nationwide the middle class is more like $40-50K (household income). If your household (how many earners it is comprised of) is over $100K in annual earnings then you're in the top quartile (25%!) of the entire country in income, and decidedly not "middle class" (though, depending on where you live, you may or may not have enough to afford a home, much less a boat, a beach bungalow, eating out, going to the bars, etc.). Keep in mind that a lot of these cities are okay for singles, but once those singles get married and have kids they rapidly discover they can't afford the big city anymore and have to leave.