I would argue this is not just true of “the new American aristocracy“; where people live has a significant impact on their lives.

Zip code is who we are. It defines our style, announces our values, establishes our status, preserves our wealth, and allows us to pass it along to our children.

On an everyday basis, living in a certain location could affect these aspects of life:

• social networks and local relationships with different groups of people (race/ethnicity, social class, similar interests)
• schools
• access to jobs
• other local amenities such as community services, recreation, shopping
• health

Now, the upper class may use their zip code in unique ways. The full paragraph that includes the excerpt at the beginning of the post suggests the zip code becomes a way to keep others out:

Zip code is who we are. It defines our style, announces our values, establishes our status, preserves our wealth, and allows us to pass it along to our children. It’s also slowly strangling our economy and killing our democracy. It is the brick-and-mortar version of the Gatsby Curve. The traditional story of economic growth in America has been one of arriving, building, inviting friends, and building some more. The story we’re writing looks more like one of slamming doors shut behind us and slowly suffocating under a mass of commercial-grade kitchen appliances.

This has been happening for decades in the United States as residents of particular races and ethnicities (primarily whites) and social class (primarily the middle and upper classes) had various mechanisms, now some illegal and others more nebulous (such as exclusionary zoning), to keep those they did not like away from their residences. And this will likely continue for decades more, perhaps particularly for the top 10%.