A historian once noted that the United States was born on the farm and moved to the city. What does this statement mean?

When the united states started out it was a very rural area, there we're no big cities with skyscrapers, clubs, and 3 hour traffic jams. the united states started out with small towns, small building, saloons, and horse carriages as a form of transportation. all of the hectic city life came with the advancements in technology.