That was because Zoro couldn't even stop nails while Sanji stopped arrows with his body.
And it's a completely logical claim, just because you think Zoro's is better you shouldn't ignore clear manga panels
I'm ready to take my L if it doesn't happen, but any other time a strawhat got a lot of attention (Nami in AP, Robin and Usopp in W7/EL, Sanji in WCI) Oda came up with something weird and completely different from the classic 1 vs 1 or what they did in previous arcs. Usually, he explores their past, gives them no real fight and makes sure to give them an emotional and impactful moment (in this case for Zoro, and I'm not talking about the umpteenth badass moment).
Zoro is the fighter of the crew so I'm sure he is going to wound Kaido again but that is Luffy's fight while his main storyline is with Orochi, the fox, Hiyori, the Ringo damyo and possibly Kuina/Koshiro