And it's a flawed crutch argument anyway that Brees leaving will kill Kamara's stats. He's a great player and they could easily run more. Russell Wilson was said to be reliant on rushing production from Marshawn Lynch; how much have his numbers declined since Lynch left?
I could argue that Cam will run less as he ages, has relied heavily on his running ability and isn't a great passer, and therefore won't be leading great offenses.
I could argue that Kamara got 97.1 yards per game and CMC got 67.9, and that 30-yard gap isn't going to just disappear because Brees left.
Probably most importantly, I could argue that while both are elusive, Kamara has actual power to run over people and CMC doesn't, making Kamara much, much, much better suited to run between the tackles and even break tackles out in space as well.