"I don't dispute that there are many Kenyans, Morocans,etc. that can train at AT for 5-6 sessions a week but what about the ones that don't train this way? Specifically I am thinking of Kim MacDonald's group.
I was recently at a seminar here in Ann Arbor with Pascal Dobert as the guest speaker to talk about training with the Kenyans. Pascal is in this Kim MacDonald group and stated that they run 3 hard sessions per week max, much of it on the track. And from the examples of workouts that he gave, it seems to directly contradict the types of workouts you say are supposedly the right way to train.
Additionally, Pascal said that their non workout days are run "hard", and when questioned further said this is almost always sub 6 min/mile but not sub 5 min, which again is considerably slower than the 4:40 pace you get to in your training. They do a long run of 16-20 miles as well.
Obviously this group has had much success (Komen, BK, G Hood, Pascal, Seneca L, Kiptanui, Noah N, etc.) and from what I learned from Pascal, they are doing it very similarily to the way most North Americans are being trained at the moment. He said the biggest difference between college and post-collegiate training was the intensity and distance.
Note the part about non-workout days being done "hard." If you do the math, you have guys running 5K at 4:10 pace doing easy days at, say, 5:30-5:40 pace, which fits neatly with what Renato says about training slower than 80% of race pace not being specific. This group includes middle distance as well as long distance people. Along the same lines, El Guerrouj's coach (Kada) has described running slower than 3:00/km as "jogging" and both Coe and Morceli ran their slower, longer runs in this pace range.
Maybe the difference here between 5:30 pace being "slow" today and 7:00 "back in the day" being normal is part of the reason for the differences in performances.