LUFFY IS THE MAN THE ENTIRE WORLD AWAITS
I think people forgot why Oda is telling the story of Luffy and not anyone else.
He could have told us the story of Whitebeard, Roger, Oden and made them the central focus, but he chose Luffy. Luffy is the most significant person that walks the One Piece World, he is the man that has been awaited for generations.
The entire Oden flashaback was centered around how there will be someone that has to come in Wano in 20 years that the entire world has awaited for 800+ years. That person is the one who will liberate the Wano Country.
Roger after gaining the One Piece laughed because he realized he was too early, things were not meant for him, he’s come to the conclusion of someone arriving in 20 years that will surpass everything he had to offer.
The entire One Piece World has been in a stalemate for 20 long years after Roger became the Pirate King, no big shots have made any significant moves until Luffy has entered the pirate world. Luffy is causing rucus everywhere and igniting a true new age. Oden at the time of his death even suggests that Kaido should focus on getting stronger and that if he is worrying about him, then what’s to come in 20 years will be far greater. He says that he is just “Oden” and that he was born to boil basically saying that this is not his story, but someone that also awaits the dawn of the world.