Everybody would die. Even Zoro... That birdcage would kill Kaido, WB, Roger, Ryuuma, Joybou, Im-sama... The worst thing Oda made at Joker's character. If G4 Luffy tried to KKG the cage he would have lost his arm.
Why would the cage kill KAIDO?
Are the wires in the cage made of ADCOC?
The cage cannot penetrate KAIDO's scales, its points are like a sharp knife only.
The cage is a stopable skill, ZORO and FUJITORA tried to stop it by pushing it, but they didn't try to cut it or use ASURA on its wires.
Doffy's strands can be broken with brute force, as does his defensive web in the clash of finishers, which was crushed by KKG.
HAKAI is making the cage look like child's play, HAKAI destroys the cage and kills the doflamingo in the process.