I can't explain it. Neither can you.
But I'm enjoying watching you try.
Not sure what you mean. To summarize:
1) It's clear the coaches have a FAR better option than either Randle or Dunbar in Murray and are using it, regardless of the wear on Murray's legs.
2) Parcells would run the ball even if it meant minimal gain. The prospect of minimal gain (either from running backups or failing to get a closing 1st down) scares our coaches into other choices (better runners, foolish passes that don't burn clock).
3) I personally would run Randle and Dunbar more (even though I don't care for Randle) to preserve Murray. Our coaches refuse for the reasons above and fear of losing.
4) I can't blame the coaches too much (yet), because Murray has carried them to 4-1.
I'll also add that Parcells admitted he shortened Joe Morris' career in the 1980's by running him too much. Our coaches aren't learning from that mistake, but (shockingly enough) our GM has.