Meh sure the Momotarou thing will happen, and Zoro will not have a 2nd round with Kaidou
But Zoro will have 1 last final interaction with Kaidou. I can be damn sure about this
This is a Samurai Arc, the arc where Zoro is the 2nd most focused SH.
If Sanji could have 1 final moment with Big Mom in the form of Wedding Cake.
Zoro will have 1 final moment with Kaidou in the form of Sword/cutting Kaidou's head off.
Doesn't matter if he fights King later.
It's like saying Zoro wouldn't shine anymore after beating Ryuma.
So my fellow ZKK believers, never lose faith.