They don't have to show it. We know they can do it, because they can coat their attacks in CoC. That's literally what we are told is happening. You take CoC, and coat your attacks, just like you do with flowing haki and CoA. There is no next level CoC required, in order to be able to coat your attacks with them. Next level CoC is destroying environments, and paralyzing people.
And no, Luffy wouldn't have been able to use it long before FS and ID, because Luffy didn't know how how to flow his Haki, prior to that. Flowing Haki is a requirement. Took Luffy 2 seconds to be able to coat his attack in CoC once he realized it could be done. Took him two weeks to learn Internal Destruction.
2 weeks for CoA compared to 2 seconds for CoC. CoC is by far and above Luffy's Haki specialty.
And no, Luffy wouldn't have been able to use it long before FS and ID, because Luffy didn't know how how to flow his Haki, prior to that. Flowing Haki is a requirement. Took Luffy 2 seconds to be able to coat his attack in CoC once he realized it could be done. Took him two weeks to learn Internal Destruction.
2 weeks for CoA compared to 2 seconds for CoC. CoC is by far and above Luffy's Haki specialty.
Kaido and Big Mom can coat CoC without knowing ID. Yamato is proof of this.
Even flow of CoA has never been said to be a requirement for CoC coating. It could be but whether it is, idk.
It seems that Luffy's specialty was blocked off by his lack of talent for CoA...
If he learned to flow haki in Alabasta like Zoro, he could have been using CoC coating all this time...
Destroying the environment is just a pressure around haki user, the same thing that splits the sky, cracks the ship or the ground like in the case of Luffy vs Katakuri... If there is such a thing as another step of CoC, we have not seen it yet.
Anyway, we should go back to black blades and the inability of top tier blade users to forge them black.



