As we all saw in Chapter 931, Big Mom washed ashore in Kuri Beach. Chopper and the others found her alone there.
There was nobody from her crew, not even the Queen Mama Chanter. When she woke up we found out that she lost all her memories.
The majority of readers and YouTubers were mad at Oda for using such plot device. But then I figured out that something’s off with what happened in Chapter 931.
In Chapter 911, when Luffy and Thousand Sunny drowned, they both appeared on Kuri Beach. It’s the same sea current so of course it’ll transport them to the same location. In Chapter 930, Big Mom’s crew drowned. I know that Oda showed us Linlin drowing and no one else, but i highly doubt she’s the only one who drowned after such a fall.
Now surprisingly in Chapter 931, Big Mom was the only one of her crew on Kuri Beach. The ship wasn’t there as well. What I think happened is that Big Mom’s family always had a plan to erase her memories and leave her somewhere outside Totto Land. They were waiting all this time for the best opportunity.
The whole crew washed ashore in Kuri Beach, they woke up but Big Mom was still unconscious. They erased her memories ( Pudding’s ability ) and left with the ship. That’s why the ship itself wasn’t there on the beach when Chopper arrived.
The past repeats itself. Big Mom’s children did to her the exact same thing that her parents did when they left her in Elbaf. ( excluding the memory wiping )
I also think that this might be the reason why Katakuri kept asking Luffy to get up whenever he knocks him out. And this was the reason why Katakuri smiled when Brulee told him that Luffy escaped from Totto Land, because he knows that Big Mom will go after him, and she’ll finally get out of Totto Land so the opportunity they’ve been waiting for will present itself. Luffy is the bait they needed, and Katakuri wanted him to get out of Mirror World alive.
Big Mom wreaks havoc in Totto Land because of her hunger issues, and she doesn’t hesitate to kill her own children when she’s on that state, so her children planned to get rid of her. If they just leave her somewhere and go then she’ll pursue them to Totto Land and she’ll destroy them. So what’s the best way to get rid of such a scary Yonko ? Leave her somewhere outside Totto Land after erasing her memories.
In conclusion, I believe that Big Mom’s crew woke up on Kuri Beach, while she was still unconscious. They erased her memories with Pudding’s ability, took the ship and left Wano Country.
*Theory by Admiral Ryokugyu