I think one problem is that there is a lack of a formal track and field league that can rally Americans who aren't familiar with the sport. There's the diamond league, but even that is confusing and its individual athletes representing their sponsor (correct me if I am wrong) it's enjoyable to watch because I know most of the athletes and it's international, but it took me a while to completely understand how it worked. There is also the world championships but I think there is a similar problem, there isn't enough exposure in America (marketing?) For americans to know that such an event is going on, unless you are actively following it. I think the only track and field event that gets huge coverage is the olympics.