This is revisionist history. Go watch the early games from last season, particularly the KSU game. He's all over the field doing just about everything but being given the ball (except the last play of the game when he had to carry half the KSU defense four yards into the endzone after getting hit two yards behind the line of scrimmage). Not sure what happened off the field or who to blame, but there was clear separation in ability and certainly equal effort during games between him and Porter the first half of the season.
Lots of reporters were asking about it. Mensa is Mensa, but his response when asked why Warren wasn't getting more carries was just stupid:
"Puzzling to some has been Texas’ reluctance to use junior tailback Chris Warren III , a 250-pound battering ram who averages nearly 6.6 yards per carry over his career and ran for 166 yards in a win over San Jose State. In losses to Maryland and USC, Warren got just 10 carries for 46 yards.
Herman was asked why Warren didn’t get the ball more often against the Trojans. Against Maryland, an early 27-7 deficit forced Texas to abandon its running game, but the Longhorns never trailed USC by more than seven. Warren carried the ball just once in the second half against USC and caught one pass for 11 yards in the fourth quarter.
Herman noted that Warren averaged only 3.8 yards on his four carries against USC. By that measure, Warren would have scored from the USC 3-yard line in overtime. Instead, the play call had freshman quarterback Sam Ehlinger try to power his way in over left tackle and his fumble set up the Trojans’ winning field goal . Texas’ first drive of the game was stopped on 4th-and-2 when, instead of testing USC’s strength with Warren, Ehlinger was dropped for a 3-yard loss.
“We’ve got to find a way to get (Warren) more yards, but in the middle of a game when you see how that is shaking out, the definition of insanity is repeatedly performing the same act and expecting different results. To keep going back to 3.8 yards per carry, I think there would be some criticism there, too. ‘Tom, why did you give Chris Warren the ball 20 times if he only had 70 yards?'” Herman said.""
https://wtop.com/ncaa-football/2017/09/texas-offensive-woes-start-with-absent-run-game/