Oda wants to wrap up all the other fights as soon as possible.
He probably wants to conclude the war in less than 2 volumes.
Nah it'll be longer. The final fights always last several times longer than any fight. I do think volume 102 (Ch 1026-1035), will certainly have everyone defeated save for Kaido, Big Mom, and likely Orochi, but those Yonko battles will probably be immense.
Seriously, consider:
- 770-779: all the Doflamingo family defeats
- 780-791: Literally just Luffy vs Doflamingo lol
Luffy vs Crocodile (rounds 2 and 3) lasted like 15 chapters lol. Luffy vs Lucci lasted like 10 after every fight. Luffy vs Kata was nearly 20 on its own. Of course this includes everything else happening outside of their fights, but you get what mean.
A ton of stuff needs to be resolved, including the Yonko fights. I'm guessing volume 105-106 will be when they fall.