How do you know he couldn't? All the flashback was about praising Oden, and even when he fought Kaido, kaido has to rely on 5k men, a snitch among the few men of Oden, and a trick. And before the trick, the narrator - Oda - was saying how much despite all the preparation, Oden was incredible and did better than all expectations. During what we saw from the fight, Kaido was just getting soloed like an abused dog - not any single panel where it was even an equal fight - so much that his allies were afraid of him to lose, and had to create a trick for him to win. It's a clear sign for those who understand Oda's pattern, that when you win like that despite beeing humiliated all along, with a trick, it means you can't win with proper methods. What conclusion do you take from this?
Because it was shown that he couldnt. No upper hand in that clash. No one sided stomping like you are trying to paint it from the clash against the dragon form. Kaido was always stronger than Oden, stronger than everyone 20 years ago by Oden's own admission.
Yes, we know Oda was wanking Oden, that much is clear, it doesnt change anything regarding Kaido's strength.
Kaido wasnt soloed like an abused dog in Orochi castle, if Oden could have done that he would have. Stop talking nonsense.
Again, besting Kaido's dragon form is nothing impressive, stop making a bigger deal out of it than it is. Scabbards were rag dolling his dragon form easily as well, all they lacked was more firepower, there is nothing impressive about trashing his dragon form. Find me someone trashing his base or hybrid form. You cant. It is clear for anyone who understands how fights work and how storytelling works is that Oda was giving Oden a proper goodbye.
There was never a proper fight between Oden and Kaido, you assume too much from one attack which Oda allowed to happen to make Oden look good because the guy was about to die anyway. He couldnt defeat Kaido, that much I guarantee you, it was seen in their clash in Orochi castle.
Likewise couldn't Base Kaido do anything to Oden in the castle though. If Base Kaido could've defeated Oden at that time, he would've done so, but he continued to go along with Orochi's blackmailing plot.
Yes, Kaido didnt have the upper hand either but that's not the point Oda was making.
Kaido didnt want to fight Oden at that point BECAUSE he didnt like the odds of Oden's and Hyogoro's forces joining hands.
He didnt care about Oden's individual strength, he cared about numbers, which is constantly overlooked by power scalers...
Kaido was already the strongest back then and it is irrelevant. He delayed the fight until he broke Hoyogoro's forces slowly.