No surprise. American networks have been like this for years. They seem to have come to the conclusion that US TV viewers can't watch any more than 400m of continuous running. That's why when they cover a 1500m race the need to cut away for a commercial, a special feature, or head off too another event, because the guru's at the networks figure that no one could stand actually watching 3 - 4 minutes of running!
The strange thing is, this phenomenon is only existant in the U.S. Even in Canada, right next door, we tend to get start-to-finish coverage of many to all of the middle distance and distance running events when shown by the CBC, for the Olympic Games, the World Championships and the National Championships. I have spent some time in Europe and in Africa and its the same there - start-to-finish coverage in most cases.
I feel sorry for US TV viewers.