i've been saying this for years lol
2022
giddens - 7.6 ypc (juck function though)
vaughn - 5.4 ypc
2021
ervin - 5.0 ypc
vaughn - 6.0 ypc
1 ypc difference is not small. but ervin is not a p5 running back. there is definitely a big difference between a good and bad running back. but good vs great? small difference. big diminishing returns after some point.