Its the truth, Luffy asked her to join she said she'll stay for now. She's a straw hat.
Yeah Luffy asked her to join, but it's still not the same situation like Vivi.
Vivi was actually with the Straw Hats throughout the entire Alabasta Saga, traveling around with them and interacting with them as well.
She actually felt like a Straw Hat, Yamato doesn't feel like that at all. Her only role was in the Wano arc, and the only Straw Hat she really had the most interaction with was Luffy.
Honestly Kin'emon kind of had the more Vivi role than Yamato.
Its not even like that, because Vivi outright could never be a SH. She always had a duty to her people, even moreso now that Cobra is dead.
Yamato is in a Jinbe situation.
- she wants to join
- Luffy gave her an invite
- she can't join due to some sort of conflict that will eventually be resolved
Like no, unless Yamato dies, she will become a SH.
Why the fuck do you suddenly want Yamato to join? If Oda wanted her to join then he would have had her join by the end of the Wano arc.
The fact that didn't happen, shows that Oda has no plans for Yamato to join the crew.
Don't get me wrong I could still be wrong but for now she's not joining at all.
Also Yamato's situation is not the same as Jinbe, Jinbe couldn't join at first because he was Big Mom's subordinate during that time.
Jinbe had a pretty good reason why he couldn't join and during the end of WCI when he did finally joined, he had to deal with Big Mom's fleet which is why he couldn't go with Luffy and the others.
But when it comes to Yamato, there was literally nothing holding her back from joining with Luffy and others.
As for Vivi, yeah back then she couldn't join but this time it's different.
Vivi can't go back to her Kingdom, do you not understand that? The World Government is after her, if she goes back to her Kingdom then she is going to get captured.
Also she's not going to be safe with Morgans and Wapol for that long and I highly doubt she will stay with them for the rest of the series, but if she rejoins the Straw Hats then she will be way more safer with them than with Morgans and Wapol.
Vivi along with Morgans and Wapol are also seemingly near Egghead as well, right now Vivi has a way more higher chance of rejoining the crew than Yamato joining.
And finally unlike fucking Yamato, Vivi actually traveled around with the Straw Hats and again interacted with them. She's a character that everyone has known for a long time, her joining does make sense but as for Yamato nah it just feels forced.