I don't disagree. It's also possible instead of making a 15 yard run, like Sony does with a huge hole, Chubb busts one to the house too. That season, Sony's longest run (before his 40 yarder in the playoffs) was 34 yards and he averaged 4.5ypc. Chubb that season (also his rookie obviously) was busting runs for 63, 41, 92, 40 and about a dozen others of 20+.
Let's also not forget that Chubb was doing this on the Browns team with very little firepower that defenses had to focus on, while Sony was running through holes that were created by the gravity that Brady, White, Edelman, Gronk demanded from the defense.
I loved Sony that year, but if the question is could a replacement level back have done what he did that season, my answer is absolutely. I used to call Legarrette Blount "Mr. Minimum" around here too, because IMO, he you could always count on him to get you the minimum amount of yards that a play was designed to get. Nothing more, nothing less. Sony was a lot like that, and frankly, I see a lot of similarities with Rhamondre too. Guys like Chubb (when he was healthy) and CMC are taking those 15 yard holes and turning them into 40-50 yard runs.
Of course, it's all hypothetical, but if we're going to argue that he could have fumbled, we could also argue he might taken it to the house because while he was slightly more likely to fumble than Sony, he was also a lot more likely to turn those 331 yards over 3 games into 450 yards...