Can't speak for others, and I agree with all who say the times years ago were subject to all kinds of issues, but we had some true freaks on the team when I was in HS. The fastest kid had serious speed, 4.3 according to coaches, and was athletically on track to choose between football and track anywhere he wanted to go. While I doubt he could have ever qualified academically, he didn't get the chance anyway as he decided he could do better selling dope after his junior season. I don't claim the 4.3 was accurate, but he was absolutely incredible.
Next fastest was a really good dude. Coaches timed him in the 4.4 range as a sophomore, but his knees got worse every year. Don't recall what he timed by senior year. It as still fast, but nothing like where he started, and his ability to change direction was seriously diminished.
Next was a dude who I believe could have gone all the way. I don't recall his exact weight, but it seems it was in the 240 range. His deadlift, squat and bench combo was 1400lbs and he ran a 4.6. He was also dumb as a box of rocks. If I recall correctly, he went to TN Tech on scholarship, but was out after his first semester. There were a handful of others who were genuinely fast, but few of those who made a college team finished for a variety of reasons. I recall one lineman who was big, fast and mean on the field receiving offers from UT, AL, Notre Dame, Miami and many of the other bigs deciding to go to Martin in order to stay close to home. Honestly don't know what became of him.
I say all this to say, there were quite possibly more truly fast athletes at a lot of schools than some are giving credit. But, at least in my experience, other things prevented their ever exercising that potential. Oh, I graduated in '86.
Got it you played high school with a "true 4.3" guy, and the next fastest guy was a 4.4. You do realize the NFL combine record was a 4.24 recently broken? To assist, I am very close to a young man who was horrible academically, yet he was fast through his schooldays. A small college put him on track scholarship which got him noticed by the US Olympic team and he traveled all over on various junior teams enhancing his technique and speed. He ran an Olympic trials final in the 200 and came in 4th not making the team. He could not run a 4.3 or 4.4 forty. When you actually run 4.3s and 4.4s you get noticed and people are around to ensure you pursue improving that talent. Your experience of multiple 4.4 guys on a high school team is one where you should count yourself fortunate.