If that is "The American Narrative" how did Chicago or New York City ever happen? How is it that a majority of Americans live in metropolitan areas rather than further out where they can more "elbow room" ?
The European conquest of north America and subsequent repopulation with immigrants (alongside a vastly diminished indigenous population) created an ethos and an opportunity for people who wanted to live away from everybody else to do so ... by pretending that the continent had been empty, and because of the need for natural resources, this was relatively easy to do.
But alongside that process, Americans were building some of the largest cities in the world, developing and improving "urban technologies", and generally pushing the boundaries of what cities could be (a role now largely taken over by SE Asia).
Any explanation for the structure, placement, demographics and dynamics of American society that focuses on single reason for things (whether it is "elbow room", "Robert Moses" or "racism") is going to be wrong about most things.