NY Times used data from Strava to write the article, and there are other sources as well. Like this study from 2017:
A Comparison of the Energetic Cost of Running in Marathon Racing Shoes
> Conclusion
> The prototype shoes lowered the energetic cost of running by 4% on average. We predict that with these shoes, top athletes could run substantially faster and achieve the first sub-2-hour marathon.
Not that easy. NYT data shows not only 4% increase for VaporFly, but also 3% increase for Streak.
Springer is harder. Though 18 male aren't enough to prove anything, the data is quite consistent. But 4% equals to 5 min in marathon. That means that a lot of athletes from 2013-14 could break 2 hours in that shoes easily. Probably 5 min on a treadmill at 18 km/h has little in common with 2 hours at 21 km/h.
