The question is: without considering two like prepared genetic clones performing side by side can we attribute who’s ahead of who, and where in the race, to head/cervical spine position alone? Answer- no.
While I am in total agreement with you in regards to optimal geometry aka force: posture, there are many other factors that could have contributed to each sprinters acceleration versus maxV.
Also, in the tone of devil’s advocate, similar to the discussion surrounding Ben’s higher maxV in the 9.83 and lower maxV in the 9.79, one valid supposition could be that Greene might not have had the 60-100m performance that he did if he had expended more energy during acceleration…
In any case, that’s a great video to get a look at the context of this discussion regarding top class athletes.