A couple of thoughts:
I hope everyone is aware that if a load is applied slowly (like a heavy truck crossing a bridge), the thing absorbing the load (the bridge) deflects slowly. The faster that truck drives across the bridge, the more deflection has to be absorbed, because the bridge has to absorb both the deflection due to the load, but also the deflection caused by the movement.
The same thing applies to tires. The faster the tire goes, the more stress the tire encounters. You won't find that part reflected in anything you can measure as the tire is traveling. It affects the point at which the tire failures due to fatigue.
So if you test tires under carefully controlled conditions, you will find that otherwise identical tires fail earlier at higher speeds.
In the real world, there are many, many things that affect the life of a tire, so it's difficult to see this affect unless you have a large sample size. A large fleet of vehicles certainly helps see this picture more clearly.
