We have 2 average backs at best. We certainly don't even have one top 15 RB. I like Hightower as a 2nd back, but he's not an above average starting back. Beanie is one of the most disappointing players in the league, and not only can't stay healthy, he isn't effective. Maybe the light will turn on ala a Darren McFadden, but I'm not holding my breath.
Considering we have the worst qb trio in the league, and one of the worst in recent memory, do you assume the entire coaching staff is somewhere beyond stupid, and is avoiding the establishment of a run game for a particular reason? Knowing how weak our QB play is, and bringing in guys like Faneca, and starting Brandon Keith, doesn't that indicate that the team would prefer to run and have a more run oriented offense? It's not that we don't want to run, we can't, especially not consistently.
The fact of the matter is, while we average 4.5 ypc (boosted by several TH breakout runs), we're also 28th in the league in rushing, and can't grind out the tough yards or control games with our running attack. I doubt the plan before the year started was to feature the talents of DA and Wingnut, but because the running game can't be depended on for consistent production, (and constant fumbles) it put the ball in the hands of the qb clowns. Add a joke of a defense into the equation, and you get a 4-9 team with the easiest schedule in football.