I said raw land, not new land. By "city" I mean built up area, not the farm fields in the outskirts. New housing in cities isn't greenfield development, it's redevelopment. It's a completely different animal with much more complex servicing and brownfield clean up issues than straightforward greenfield product. That's why it's more expensive. And yet it still happens because there is a demand for it.
Again, my whole point is this 2020 "white flight" phenomenon is a lot of talk and interesting opinion pieces. Let me know when there is a price inversion and Staten Island housing becomes more expensive than Manhattan. I could be wrong. It might happen someday, just not this day.