Why Do We Work So Hard on Our Lawns?:
The answer is a combination of habit, snobbery, capitalism and government intervention.
I live in a relatively new construction development (as there is so much in the Charlottesville area) and could not agree more with this –

Only with the birth of the suburb could Americans finally realize the ideal of carpeting a buffer zone between themselves and the rest of the world. The lawn was essentially decorative fringe: Its value arose partly from its impracticality. Thorsten Veblen noted in his 1899 book, “The Theory of the Leisure Class,” that grazing animals had been banished from yards because they gave “the vulgar suggestion of thrift.”