You get a line that can effectively block, and the re-animated corpse of Walter Payton can get you 4.2 yards per carry.
We don't need to lead the league but we MUST get consistent yardage on a running down. We don't need to pop for huge yardage but we cannot have the kind of game where we have an enormous number of runs of 1 yard or less. Even three yards on a carry make an enormous difference in makeability on your next play. This also translates into effective short yardage running - if we need one yard, we need to be able to run for one yard. Don't need five, just one. And that almost always comes back to blocking.
As noted, Murray has health issues, but I still believe the key is not the runner per se but consistent blocking at the line.