So let's put this myth to bed once and for all that Kaido is awakened, and Oda just didn't want to show it. Too many threads popping up about this lately, when we've already been given the answer in the manga.
Kaido was introduced as a character who is deemed unkillable. Nobody, not even the man himself is capable of doing so.
During the Luffy vs Kaido fight, we learned what it takes to awaken a Devil Fruit, and that is the fact that the user essentially has to either die, or be pushed so close to the brink of death, that it is in that moment they can fully synchronize with their devil fruit, and awaken.
That is impossible for Kaido, or at the very least, has been the case his entire life. He hasn't awakened because nobody has been able to push him to the point of doing so.
The conclusion of the Luffy vs Kaido fight makes this interesting though, because for the first time in his existence, we can say he's on the brink of death.
Oda can fully capitalize on this if he wants to, and have a fully awakened Kaido, emerge from Wanos volcano to participate in the Final War,which I would not be surprised in the least if he does this.
