Better stats or talent in high school does not mean better talent or stats in college, the same way better talent or stats in college do not mean the same in the NFL.
That is true. But when you have better stats (on the same team), better size, better speed and better athleticism...well, there isn't a whole lot left.
What about the most important factor for a RB - Vision
The thing is, I think Cook has great vision as well. You know this better than I do, but you can't dominate that caliber of competition on pure athleticism. Cook sees daylight first, and then has to speed to pull away.
If Yearby was more of a pinball-type tackle breaker, I'd feel better about his lack of speed. But Cook was actually harder to bring down in the three games I saw this year. The Grayson game (GA school) is what scared me re: Yearby's star potential. The whole team looked overmatched, including Cook, but Yearby really struggled with their size and discipline.
Yearby's big advantage over Cook, IMO, is his overall efficiency of movement. But I don't see that closing the gap in physical gifts, especially considering that Yearby may have plateaued a bit and Cook continues to make leaps.