Perhaps it is a simple lack of wonder about going fast. Cars can go fast but most people don't drive them over 70, 75. What is 200 mph to them? NASCAR promotes speed at a lot of tracks but to most people whether they are doing 100 mph or 200 mph, its still cars going around in circles.
People don't want speed, they want drama in the form of wrestling or UFC. Even at that, it is a soundbite world and there are not enough soundbites for anyone in a race that lasts hours.