At least for my family's farm in OK, a lot of the labor moves and takes the equipment with them. They move north to south with the season and the farm owners don't have to own as much equipment (in our case, none of us are farmers and haven't been for a few generations so a different situation). The farm manager still farms his own land, but he uses this same labor and their equipment with own a little of his own for tending during the growing season (the most labor and equipment intensive parts are harvest and planting).

Point being, the expensive equipment that is effectively being rented (with the labor in our case) isn't sitting idle most of the year. It's being used in different areas.