How is Ichabod Crane’s failed pursuit of Katrina Van Tassel a metaphor for the inferiority of society compared to nature?

Ichabod's failed pursuit of Katrina Van Tassel works as a metaphor for the inferiority of society compared to nature, because Ichabod himself represents a man obsessed with some of the worst aspects of society.  He is a school teacher but feels no particularly strong calling to the profession.  Rather, his interest stems from the ease with which it allows him to exploit the families of his students "who happened to have pretty sisters, or good housewives for mothers, noted for the comforts of the cupboard."  He uses and abuses the system for sustenance. 
Similarly, his interest in Katrina is based not on sincere affection for her, but rather for the land that she is set to inherit via her father, Baltus Van Tassel.  Ichabod's

heart yearned after the damsel who was to inherit these domains, and his imagination expanded with the idea, how they might be readily turned into cash, and the money invested in immense tracts of wild land, and shingle palaces in the wilderness."

If Ichabod succeeds in his goal, he would turn the profit from the farm into the acquisition of additional land.  In order to achieve this end, he courts Katrina in much the same way that he learned to court the families of his pupils.  However, he fails because Katrina desires another: the much more sincere Brom Bones.  With Brom, what you see is what you get.  He doesn't pretend to be something that he is not.  He is straightforward, perhaps too much so, and he does not hide his intentions.  He is interested in Katrina for Katrina,  not the land she will inherit.  He represents the uncivilized, untamed spirit of man.  In the end he succeeds where Ichabod fails, and in turn represents the triumph of nature unbridled.