In my opinion this is not the end of Wano. Kaido has been fighting nonstop for 63 chapters (he fought Big Mom for 3 days, then he fought the Nine Red Scabbards, the 5 Supernovas, then Luffy, Yamato and finally Luffy again), with incredible feats of strength and getting constantly attacked. Without eating.
Kaido is extremely durable and has high endurance, but he is tired and weakened. He’s begun to falter in the last fight with Luffy.
It has been suggested in Chapter 1049 that Kaido is only “defeated” when he is hungry and this is mentioned in the same chapter as his fall. Oda is subtly telling us his next plan for the arc.
Furthermore, Kaido is a pirate defined by his defeats – he is the only character in the story so far with such an introduction.
We also know that there is currently a festival with FOOD going on right now, where Kaido is conveniently by right now. This is a big chance for Kaido to oppress the Wano citizens, steal their food, and regain his strength in the Flower Capital.
A similar moment happened just 30ish chapters ago, where Luffy had eaten his full from Caribou’s stash for a comeback in Chapter 1021 (as well as many other moments in the story).
After all the raid members are currently being flushed out of Onigashima with the water of Zou, the Wano cast will be in the same place. Everyone has been separated up until now, but Onigashima has landed and the battle is on an open playing field now.
The story isn’t finished here – Kaido’s flashback just started, Wano country is not open, the people are still hungry, Kaido is not out of the country, etc…
Kaido is all about betrayal and individual strength, and Luffy’s crew still needs to prove his ideology wrong. He is the antithesis of Luffy as an individual. Oda WILL wrap up these plot threads, and we are finally reaching the climax. Oda is telling us what will happen straight up with these two lanterns on the final page of Chapter 1049
The main objective will change from defeating Kaido on Onigashima to saving all the Wano citizens IN WANO. Kaido’s defeat needs to be witnessed by Wano citizens.
Act 3 still isn’t over, but the end is in sight.