I don't think you realize how often elite RBs lose yards.
In 2007, Lawrence Maroney had a success rate of 58%. Success rate is runs of 4 yards or more on 1st and 10, 60% of required yards on second down, 100% on third down. A negative run is always an unsuccessful play.
58% was good for 2nd in the league.
That's an amazing statistic. May be you're right, my standards are just too high. Maybe it's biased because there SEEM to be so many times when he could get 4 yards but gets 1.