Interesting.
I think there MIGHT be a little truth in it.
I don't think it's just for very high mileage.
I'd say you generally should avoid workouts that tire you out in a way that you need super long recovery. It's ok to have a "ball buster" here and there but generally training should be like "punching in the time clock day in day out" like malmo said (I think he said something like that in another thread).
A huge problem for many is that they think 10 x 400 or other intervals are bread and butter for long distance running and the normal runs are "recovery". BOTH are important, BOTh are TRAINING and most important are the endurance runs for LD running.
Pikachu