Go back and watch some of the tape.
Some guys quit. They didn't quit on every play but they quit on some/many. RBs don't run for 200-300 yards before first contact with 11 guys on defense going full out every play.
The difference being if I was ever hired for a position I wasn't qualified or ready for, I would sure as **** hire a badass team around me to make me look good and learn from.