The large number of first downs on the ground suggests that they are effective. DVOA takes this into account. For example, a 2 yard run on 3rd and 1 is effective, even if it does not look good on the stats. Ditto for short yardage TDs.
However, I suspect that many of the yards we have come when grinding out teams in the 4th quarter when they are beaten already. Going with the eyes (which has some risk), I question our ability to impose the will by running the ball when it counts.
But, I do think the running ability is better than usually portrayed.