I think it boils down to ego and spite. Americans love the idea about dismissing things that are not “American” this is why F1, WRC, Soccer, etc don’t do well in America. Plus I don’t think Americans are dumb (maybe a little slow some times). But Americans (and others) want instant satisfaction if it doesn’t come easy then they don’t want it. The sports I listed take time to learn. It’s easy to watch cars that look the same go around in a circle. It’s easy to watch American football. I really think it’s that simple. Plus we only have speed TV in the states and they cover a ton of nascar.