The Dallas Cowboys' identity as a team is their running game. You know it, I know it and every team in the NFL knows it. The Cowboys have built their entire team with this identity in mind.
It's why the Cowboys have allocated a ton of their resources to the offensive line. It's why they took a running back fourth overall when most teams devalued the position altogether. It's also why the offense tends to sputter when the running game struggles to keep the Dallas offense afloat, forcing a floundering passing attack to pick up the slack.