The stack height on these prototypes certainly doesn't look anywhere near as beefy as the 4% no doubt it is using the zoom x foam - but obviously somewhere between Rio and Monza they worked out more foam was better. I mean look at the Next% and Alphafly for where they ended up going. So I'd suggest there was significantly less benefit in wearing this shoe in Rio than the studies have suggested especially given the race only started in the last 7k.
Also you sure one of the women isn't wearing the prototype or is she wearing a Lunaracer? She certainly isn't wearing a Streak.
The beauty of this is the first study to come out - the one that showed a 4% improvement and is well regarded scentifically according to Geoff Burns even if it was funded by Nike - was actually done on the Vaporfly prototypes used in Rio.
As for the women's racers, Geoff Burns, who is an expert on this, thought that Sumgong might have been in these shoes but I showed him the photos from Rio today and he said they were all Zoom Streaks.