I think it is that parents just don't kick their kids out the door as much as they used to. I think the demise of sandlot sports has had a lot to do with it.

Army. 0 (1974)
5000 meters - 13:26. Cierpinski was later implicated as a part of the state-sponsored doping program of his country by East German track and field research files uncovered by Werner Franke at the Stasi headquarters in Leipzig in the late 1990s.

Frank Charles Shorter (born October 31 1947) is an American former long-distance runner who won the gold medal in the marathon at the 1972 Summer Olympics. His victory is credited with igniting the running boom in the United States of the 1970s.