To have a guy rush for 10,000+ career yards, straight-line speed isn't a top requirement.
1 - Vision
2 - Injury-avoidance
3 - Durability/High volume
4 - Moves/Agility
5 - Speed
I'd rank the attributes like that........vision is #1 - both vision to find the hole/cut back/progress through the quagmire AND vision to avoid big hits/surprise hits/etc - because those can cause fumbles and injury.
#2 and 3 on the list do not align, which makes it so hard to be a 10,000 yard rusher. You need lots of carries, BUT - you need them by earning them (being productive) and you need them while not sitting out from injury due to them.....AND not getting too many of them in a given season. RBs tend to have bad years following a career-high carries load. I looked this one up - Emmitt has the most carries ever, but ZERO seasons in the top 20 all-time. That matters.
RBs rarely run in a straight line. They're almost always shifting and hopping, cutting, and stutter-stepping. Not just juking defenders, but setting up blocks, being patient, and navigating that mass of humanity in front of them. Getting 3 yards instead of 2 by being shifty and falling forward is incredibly underrated.
I view speed as being needed and the most useful when you're deficient in the first 4. Speed can make some of it up. And I'd go so far as to say if you have the first 4 AND great speed, you're screwed, because you'll get the ball so much that #2 becomes impossible.
