After Zoro got it most Luffy fans accepted Sanji would get it. Then after Gabans intro, Sanji getting it was the prevailing assumption. Only a loud minority was denying the obvious.
Just go back to any old thread, even luffy fans denied sanji the conqueror pass.
Post Gaban, it might have changed for some people but it didn't for me. Gaban was a weapon user, Haki or DF was the only vertical investment he could have made.
Whereas Sanji main power source was his Flames and diable jambe, with exoskeleton Ifrir jambe.
Haki yes made it a little stronger but apparently no haki bloom moment for him whatsoever.
There's literally no build up for him to go that route now.
It's Giving Zoro a mythical zoan expect him to fight with it destroying everything Oda has built for Zoro for decades in swords.