Maybe it was stated too simplistically, but it is NOT asinine.
In 1980 the WR's were 7:32, 13:08, 27:22. For 10 years they remained relatively intact, in so far as they were lowered but not extremely. They were not bettered many times either. Since shoes had reached top levels, tracks had also, and the way training was done was not in any serious flux either like it had been in the 40's, 50's and 60's.
All the pieces had evolved to a point where further refinement was NOT going to yield huge improvements, only marginal ones. During the 80's the records did improve a little, about the amount that history would predict and the improvements were by a small number of people.
Then came the 90's and the 10k WR is 60 secs faster, the 5k WR is 29 secs faster and the 3k WR is 12 secs faster than the standards that Rono set that 6, 7, and 8 years repectively, and were only improved incrementally when they were broken (with the exception of Moorcroft's 13:00.42).
So, what was it that allowed 10k's 40 seconds faster than Barrios and Ondieki? 50-80 seconds faster than Vainio (who DID DOPE), Cova, Viren, Rono, Salazar, Schildhauer and all-time great Lopes? 5k's 30 seconds faster than World #1's in the 80's like Mamede, Kunze, and Rono?
The 10k is 25 laps. If you are 50 seconds better than the earth's fastest men just 10 years before, what gives? What made you improve 50 SECONDS on Antibo, Barrios, Mei, Mamede and all the world's fastest just 10 years before?
If it is something BESIDES drugs, then what kind of thing would not allow a proportional improvement at all distances? Certainly since 1988 WR for distances around 5k/10k have all improved remarkably. The 1500/mile, 2k, 3k, 2-mile, Steeple, have improved, but so have the LONGER distances like the half-mar and mar.
So shouldn't all the track distances have improved at roughly the same rate?
What kind of thing could explain the incredible improvement in the distance WR's that would yield very marginal improvement at 100, 200, 400, 800?
If you are not familiar with the rate at which the distance WR's were improving from 1993-1998, check it out sometime, it is startling.