What are you talking about the official magazine has already hinted at it.
You don't understand that type of person Kaido is. He won't give up. He's going to continue to return and that's not even talking about what powerful ability you could have from awakening. Which I still believe what increases strength and recovery power.
Luffy's definitely is growing stronger and I'm excited to see what he can do but there is no way I can believe Luffy beating Kaido, who more than likely has awakening, by himself.
Last, the Scabbards stated the battle won't be over until Kaido is dead. In the manga there is talk about killing Kaido.