That's the case all over college football, at almost every level. Running back is an instinctual position. Outside of teaching pass blocking schemes, some nuances to receiving routes and teaching run tracks, running back coaches across America primarily are responsible for reinforcing things that their elite athletes already know (such as ball security). You can improve as a running back, but coaching isn't getting you there. You either have the skill set to be successful, coupled with the vision to find daylight, or you don't.
Because, as you know, the above is true, running back coaches across America are some of their staffs finest recruiters. They only have 4 or 5 guys to worry about and they have the excess time to be outstanding recruiters.
Neither Autry Denson nor Tony Alford are elite coaches. If they were, they'd be offensive coordinators, running their own show... What separates Tony from Autry is that Tony is an elite recruiter, which is what makes him so valuable. So whether it's because he coaches kids with the god given talent of a Mike Weber and a J.K. Dobbins, or simply recruited them to come to Ohio State and be elite, the credit is still his.
The fact is that Weber, Dobbins, Adams and Williams (who will be ND's best back this year when he returns from suspension) are all Tony Alford recruits. He picked them out, recruited them and he landed them.
Autry Denson's best back recruited to this point is who? Tony Jones? An average, tweener back, who lacks game breaking speed... It might actually be Jafar Armstrong, who he didn't even recruit. Del Alexander did.
You can have it either way... You can credit running back coaches but if you're going to do that then Alford gets credit for Zeke Elliot, Dobbins, Weber, etc, etc... Or you can say "running back coaches don't matter that much, because the position is more about god given ability than coaching" and I'll buy that too. That's been my experience around elite running backs... But then in that case your comparing Alford to Denson as recruiters (relative to their value) and if you want to do that, Alford is so far ahead in that department that he can't even see Denson when he looks back for him.