I was watching the Steelers-Titans game and Derrick Henry is great. I disagree that having an elite RB is not helpful. Henry not only is great at running, he also forces the defense to focus on him which makes the passing game better.
The fact may just be that Saquon isn't that good. I imagine the Titans have a much better OLine than the Giants do, but Saquon has made a career so far of doing nothing on most plays and then breaking out one or two huge runs to make his stat sheet look good.
I hope Saquon can turn it around, but he's probably not a generational RB and probably not worth the contract he will get.