Thomas Jones actually goes against your argument as A-Train definitely took carries from him.
He did? You might want to recheck your facts:Week 1: Jones 21/Thomas 3
Week 2: Jones 23/Thomas 5
Week 3: Jones 22/Thomas 2
Week 4: Jones 13/Thomas 0
Week 6: Jones 24/Thomas 1
Week 7: Jones 13/Thomas 5
Week 8: Thomas 25 (Jones hurt)
Week 9: Thomas 28 (Jones hurt)
Week 10: Thomas 29 (Jones hurt)
Week 11: Jones 18/Thomas 0
Week 12: Jones 14/Thomas 3
Week 13: Jones 15/Thomas 15
Week 14: Jones 13/Thomas 0
Week 15: Jones 15/Thomas 6
Week 16: Jones 22/Thomas 0
Week 17: Jones 26/Thomas 0
So let's see, there was only one game the entire season where Thomas took meaningful carries away from Jones. By contrast there were five games where he did not get a single carry and a total of nine games where he had three or less.
It's pretty obvious all Thomas was last season was a backup. Jones was clearly the primary RB and Thomas was no threat to take any carries away from him -- even after Thomas had some good games in relief of the injured Jones.
Care to restate your position?