When did it change? The era is still the same
and your evidence is what? See, it's just headcanon. You said he comes back with no proof or logic in the story.
Just your delusions because how pathetic Zoro is
Kaido was fine dying in a middle of nowhere when he tried to kill himself by falling from sky island
When Kaido comes back in your delusions, then it would make more sense to lock him up in prison for the rest of his life, instead of another dozen chapter fight
Again, not a single proof to your statements.
It's like me saying
"Sengoku will fart into space and he will meet previous Joyboy, who is currently fighting Xebect from trying to enter the Earth"
Shit has no proof and doesn't make any sense