This is not as rare as you might think. There is actually a pretty good list of guys who had some of their best seasons after age 25.. beginning with Derrick Henry last year.. But to your point there is no question that wear and tear takes a toll as guys age in the game. Ironically getting hurt, missing time and having his lowest number of touches ever might have given Zeke's body a year off in terms of wear and tear. There is no question that he is going to slow down as he ages so he will have to adapt his game in order to continue to be effective. Ironically, running mostly inside and not dancing to the outside, one of the things he is often criticized for here is one of the things that will keep him employed in the NFL longer. If he is able to stay at or above 4.0 ypc and continue to be one of the best short yardage runners in the game as well as being the best blocking RB in the game will keep him getting paychecks into his 30's. I know that will anger the "I hate Zeke" crowd but that's the reality.
Walter Payton comes to mind. In four years between 29 to 32, he averaged about 1500 (1497) yards a season in a 16 game schedule. Those years he gained 5989 total rushing yards, averaging 334 carries a season.
Tony Dorsett had his best year at 27 putting up 1646 yards. And after playing only 9 games at 28, came back with 3 back to back to back seasons over 1000. (3800 total yards between 29 to 31)
But its questionable if BigMac and Kellen Moore are going to commit that much work to Zeke. BigMac had backs reach 1000 yards in only 5 of his 13 seasons. If he has the same fait in Dak he had in Favre and Rodgers he has no reason to pull the ball down. And that works against Zeke.
So a rushing title isn't out of the out of the question, but more likely he'll finish in the top 5.