The animation is deceiving simply because it doesn't show acceleration. Those starting blocks you mention will have a big impact on the initial acceleration, but ultimately, the data isn't there; we don't know what meter splits any of those medalists ran.

Regarding running shoes though, there really are no "running shoes" to speak of in sprinting. I doubt that changes in sprinting spikes have made any difference in many decades. There are only so many ways to make a toe spike plate with a negligible heel, sewn up into a room slipper.

I'm going to google for images and surrounding info about historic sprinting spikes now. [...] Hmm, one obvious difference is that the pre-1960's spikes were looong due to the track surfaces before tartan. Those nails look like what is used for cross-country today, wow. They would not even be allowed on a modern track.