Principle of Barriers
Upon rejecting God's truth, there are barriers that would hinder a person or society from endlessly and effortlessly sliding down into degradation. At different stages, God slows man down, allowing him to observe his situation and to respond to his truth. If no positive response is made, then in God's timing he is allowed to go down to another more degrading stage.
Point: No good excuse. God gives time for man to evaluate his situation. The snowballing syndrome by which man might fall without trying is avoided by the barriers. Man is fully responsible for his next step, whether up or down.