A case for density and priveledge 

“At the same time that American communities are desegregating, racially, they are becoming more segregated in terms of schooling and earnings,” Enrico Moretti wrote in his book The Geography of Jobs. In other words, today’s richest cities might not mimic the collapses suffered by the richest U.S. cities from the 1970s. “The knowledge economy has an inherent tendency toward geographical agglomeration,” he wrote. “Initial advantages matter, and the future depends heavily on the past.”