The New York Times absolutely crushed it with this video which depicts graphical comparison between Usain Bolt’s 2012 Olympic 100-yard dash final race vs every other Olympic competitor EVER. It starts as far back as the Athens Games in 1896. The evolution in speed is quite amazing and no doubt has brought up many arguments as to reasons why, with steroids also being thrown around.
Based on the athletes’ average speeds, if every Olympic medalist raced each other, Usain Bolt (the London version) would win, with a wide distribution of Olympians behind him. Below, where each sprinter would be when Bolt finishes his race.