But Sanji's (and the Straw Hats as a whole) will get increases partially thanks to Luffy's notoriety, accomplishments and status. He defeated Kaido and claimed a 3 billion bounty, his crew was involved in the raid and will get boosts simply from being under him, plus their own unique accomplishments.
Luffy getting a ×3 was solely due to his own efforts as he was captain but Zoro, Sanji and the rest of the crew are under Luffy and will get boosts thanks to him, just like how Oda explained subordinate bounties are affected by the captains', except guys like Sanji and Zoro defeated +1 billion bounty men on top of simply being involved in the raid that Luffy came out of with a 3 billion bounty.
I understand your point, we'll see I guess.