When I was growing up many of the biggest stars in the NFL were running backs. Guys like Emmitt Smith, Barry Sanders, and Thurman Thomas were not part of a committee, they were feature backs.
These guys were workhorses for their teams. They would get the ball over and over relentlessly tiring out the defense until what started with 3 and 4-yard gains started to produce 5 and 6-yard gains, and then they would pop a big one.
Times of course always change and today’s NFL is different. Running backs wear down, and the best defenses no longer tire.