I'll just ignore ventolin posts since they are just distracting.
Ngeny's lifetime PR's at 1500m and the mile are races where he was second to El G.
Lagat's lifetime PR's at 1500m and the mile are races where he was second to El G.
Cacho's lifetime PR at 1500m was in a race where he was second to El G.
Mehdi Baala's lifetime PR at 1500m was in a race where he was second to El G.
Venuste Niyongabo's lifetime PR at 1500m was in a race where he was second to El G.
William Circhir's lifetime PR at 1500m was in a race where he was third to El G.
Labin Rotich's lifetime PR at 1500m was in a race where he was second to El G.
All of the above ran sub 3:30 for 1500m.
All of them had El G in their best race.
So it seems that El G's style of always going for fast races is what really got people running fast during this time period.
Maybe Ngeny could have run 3:25.
But he would need El G in the race and El G always came out ahead when the race was fast except for one race against Lagat in 2004- 3:27.40 to 3:27.64