In my experience the 3 yards and a cloud of dust method works great if you get up by a couple of scores. Just move the chains, and the team behind chances dwindle as the clock is ate. Its hard to blow out a good ground, and pound team to as they will at least keep it close. However ive seen a spread team beat a ground, and pound team way more times in my years, A lot more. Maybe it was just who I was watching, but if the ground and pound team gets 2 scores behind its usually over as they are forced to abandon their plan, and go to the pass. Once seen a record setting team that had rushed for 6000 yards in a season get beat by over 40 to a spread team in the same class. The key is finishing the drives. When a team runs the ball that much the chance of fumbling is high. If a good run team can hang onto the ball, and not jump offsides and get behind the chains it works great, but ive seen a lot of them go down by coughing up the ball or killing drives with penalties.