San Francisco, Manhattan, D.C. -- they're all outliers. My great-aunt runs a day-care facility in Kentucky. They charge $200/month/child. (This is definitely an outlier on the other end of the spectrum)
It's very difficult to talk about wealth, as wealth means different things in different places. My argument for a $100k/year salary being "rich" falls apart in expensive cities.
True, but keep in mind, 100k is a lot easier to achieve in those cities. Registered nurses and dental hygienists (and software developers), who all earn about 110k a year (median) in SF, tend to fall well below that threshold outside these centers.
Personally, I'm glad dental hygienists make enough money that, with two incomes, they can live a middle class life where they work. But it really does put that "critical shortage of software developers" at an average of $110k a year in SF in perspective.
It's very difficult to talk about wealth, as wealth means different things in different places. My argument for a $100k/year salary being "rich" falls apart in expensive cities.