It is interesting that Usain Bolt is basically the opposite of this. His start isn't very good (for a world-class sprinter) but his top speed is tremendous.
Actually if you throw out everyone who's been suspended for PED in between (Tim Montgomery, Asafa Powell, Justin Gatlin), Bolt in 2008 was the first to run a faster time than Johnson's 9.79, 20 years later
I always wonder how much of a difference the drugs make in this. Like if Bolt was lifetime PED free, what would his best 100 m be? This fellow says that most of the improvement in the 100-m record since Jesse Owens (1936) can be attributed to track surface technology:
https://www.ted.com/talks/david_epstein_are_athletes_really_getting_faster_better_stronger?language=en
For me it's a simple matter of more genetic freaks getting into the game combined with modern training ANY top athlete can have. For example, once the East Africans had access to modern training and nutrition they started to dominate the distance events.
In soccer the USA sucked compared to most elite soccer nations.
Now, with the success of the MLS and increased popularity more Americans are taking soccer serious.
Sooooooooooooooo, the USA is getting more talent and better coaching in elite soccer now.
Jessie Owens ran a hand time 10.3 in 1936, which = 10.45 automatic modern time*
But the man ran it on a dirt track without blocks, so I'd estimate he'd get a modern track automatic time of
aprox 10.05. I think we can be 100% certain that Jessie didn't use any juice, as it wasn't invented for another 18 years.
Jim Ray Hines ran a 9.95 automatic time winning the Mexico games 100m, but that was at altitude.
It took several years after Hines before a legit sub 10 sec 100m would be run at/near sea level.
PED's have their place in this equation but since EVERYONE has access to them , the best of the best still need the most talent. Valerie Borzov USSR won gold in the 100m in 1972 with a time of 10.0 but historical records shows he was on a serious PED regime.
Ussain Bolt may not be using much in terms of PED's. He has the stride turnover of a top world class sprinter, but is 6" taller, thus he covers a few more inches each stride. If drugs were the main factor, we'd see 100's of average basketball players converting to track and running fast 100 m sprints ...we don't.
I wouldn't bet my life Bolt was 100% clean, but it doesn't really matter.
He's just a incredible genetic freak.