My guess it patents are that system. Not tractors, but I did listen to a podcast about how one of the main toothbrush manufacturers used patents to crush a gro

My guess it patents are that system. Not tractors, but I did listen to a podcast about how one of the main toothbrush manufacturers used patents to crush a group of dentist trying to make a better toothbrush for cheap. The patent holders waited until the last minute so that the dentist already had sunk their money into product about to hit the market to get the courts to stop it. We are now at the point patents hamper innovation.