Cause Zoro is a very important character we’ve been following and hasn’t shown enough to suggest he will help out that much. I’m sure Sanji is going to get involved against Kaido too, it doesn’t mean I think Sanji is doing shit to Kaido.
What about Law? He’s got feats and hasn’t shown enough to suggest that he’ll help out much either. He’s only managed to beat Vergo and Trebol, two vet level characters (at max).
If loses/inconclusive fights go you could count Doffy for Law...but then you’d have to include Fujitora for Zoro.