To stay within the engine analogy. We have engines that are more powerful than horses, but 1. we aren’t good at building cars yet, 2. they break down so often

To stay within the engine analogy. We have engines that are more powerful than horses, but 1. we aren’t good at building cars yet, 2. they break down so often that using horses often still ends up faster, 3. we have dirt tracks and feed stations for horses but have few paved roads and are not producing enough gasoline.