Although I don't necessarily agree 100% with this guy's conclusion (I'd be more permissive about it) he is deadly accurate about the '70s and '80s scene. I did one on 1979 and the same race again in '80. It was considered OK according to parents and peers. 17-and under or 18-and under was a deep division. I went under 3 that first one, and faster yet the next, but was so far back that I didn't medal in my age group at either of those. I did in some races, especially 10ks, but not that one.
This particular marathon was a significant regional race that I can guarantee you hadn't heard of unless you were from that part of that State. So I'm not talking something that brings out the talent from the whole continent, much less Kenya. This was not Boston: just a prominent local marathon. And you had to be in the 2:40s to even think about top-3 Boys. 2:50s medalled for Girls, although at 2:54 I was behind the winner of that division as well. 34 flat won Boys at a random 10k. If it was a bigger, well-known regional race, 33 was off the podium. I don't mean overall - that would be sub 30 obscure race and sub 29 bigger. I meant my age group.
This may seem shocking now, but a ton of kids were doing it. We had 4 just from one class at my school ride with my dad. We saw so many our age that we didn't meet them. It was not a novelty to have teenagers at a road race. They must not have run for their school teams. I mean, I don't really know. I didn't know them nor go to their schools, but I know where they were on a Saturday during track season, so they must not have. What's changed? Maybe some of you can explain.....