Sure. Go find me the RB that has proved they can do what Cook has done without an injury that's available. He just had the shoulder surgery he's been putting off so he should be ready to go from all reports.
It's just shooting an argument in the head for the sake of doing it. We do not have a great RB room. We have a decent RB room. If you get Cook, you have a great RB room. But let's keep hearing from people like you who just want to settle. To you, having a "far from terrible" RB room is enough which to me is also completely ridiculous.
Another reason for the desire of Cook is that Tua gets hurt a lot. He's incredible when he's in there but when he's out, we looked bad with Skylar and Teddy. Having a RB room with Cook gives our offense another way to win should Tua get injured. He as the lead runner can pose enough of a threat to allow White to still win some games. Additionally, with Cook in, you can flex out Mostert and Achane to the passing game.