Who's talking about predictions?
Again, you're saying the same thing that has been said for years. Rushing efficiency is not meaningful when it comes to winning or losing.
So, "the ability to run" is very important for passing efficiency, but not in any way that can be measured? Do we just take a vote to determine whether a team can run the ball well that day? Or do we just pretend that a team can run well when it suits our purpose? ("We passed well, so that means we had the ability to run." "We didn't pass well, so that means we didn't run well enough." "We didn't stop the pass, so that means the opponent ran well." "We stopped the pass, so that means the opponent couldn't run well." Never mind what actually happens in the game.)
You are only talking about rushing efficiency as a statistical parameter.
The problem is that the parameter is very flawed.
So what is the meaning of regression correlation (or lack thereof) based on the flawed parameter?
Not much.
My point is the ability to run is not reflected accurately by a statistical parameter that I am aware of for this.
May be there are some advanced stats that are better, but I am not privy to those.
Just because something cannot be tested does not make it irrelevant.
There are lots of things that science cannot answer - do we simply deny they exist?
My point is that the rushing attack situation is too complex to model.
Lets look at the anecdotal evidence, does drafting Zeke make a difference to winning?