Jim Ryun is still the only person to run under 4 minutes in a high school only race. Ryun also holds the Kansas 800, 1500, and 5000 meter school records. In addition that 800 (converted according to the Kansas website) is still the NCAA record. All of these were set in either 1966 or 1967 and run on dirt tracks! Remember that they also ran on clay tracks in those days.
Imagine what Ryun would have done with modern physiology knowledge and training. People do not realize how fast they actually ran in the old days.
Yes we have our handicaps today as well. All you have to do is watch guys walk down the street holding their pants with one hand and a cellphone with the other.
But we should compare athletes according to when they competed.
We do not say that Jim Brown of the Cleveland Browns was a horrible running back because he competed in the 1950s and 1960s! But that is what we do to Jim Ryun and Craig Virgin, etc. If anything Ryun and Virgin are better than kids are today!