Cowboy Bob, trailswatcher and big changes all make excellent points concerning the viewing of the sport.
To make one the most important points more simple, MOST meets at all levels should last for no more than 3 hours, if one of the goals is to have an audience. Hell, as a high school coach and as a parent of track athletes, it seems to me that most high school meets should be run somewhere around TWO hours (including invitationals) as the kids tend to appreciate the efficiency of those meets. The whole day hasn't been filled with track and there is still time remaining in the day for other activities.
If the goal is not to make the event enjoyable to watch, but to get as many athletes involved as possible, like the Junior Olympics, then let the days drag on from dawn to sunset. If the only goal at the National Championships is to crown Champions, then the current system works fine.
Here in Illinois, the stands are jammed with fans at the state finals on Saturday. Thursday and Friday are for qualifying and the stands are usually limited to the athletes, coaches and families of the athletes. But Saturday's finals bring out fans as well, and there are not too many empty seats in the stadium at Eastern Illinois U. The crowd gets loud and the kids will tell you, even after they go to college, that the state meet was the most exciting meet they ever competed at.
It's not that hard to have only finals all on one day.
As it is now, it is as though the people who run most tracks meets wish to make them an endurance event to view and as hard to watch as possible.