Often when there're several that are really good a record attempt gets derailed into something important, a Race.
Here there are so many top guys that you can't sit back and hope that you can beat five or more top guys because you're odds are not that great. So that improves the odds of a fast race.
There have been similar great fields, one was the Golden Mile where Coe ran 3:49.0 breaking Walker's 3:49.4. Walker, Scott, Wessinghage, Coghlan, Steve Lacy (who was sick and so not a chance to do well) effectively served as a 57.0/57.0 Rabbit.
