The world thought the fight was a 3v2 so kaido and bigmos bounty was divided into 3 and shared equally to luffy, kidd and law, so what do you think luffy's, kidd and laws bounty would have being if the world knew that law and kidd defeated bigmom in a 2v1 and luffy finished the fight with kaido in a 1v1. However the world does not know about the nika nika no mi.
note-
zoro and sanji who are not relatively popular in the one piece world got a lower bounty than the person they defeated, however jinbe who was a schikibukai got a bounty of 1.1 billion not because he defeated whoswho (the cp0 already expected that) but because he was a warlord
note-
zoro and sanji who are not relatively popular in the one piece world got a lower bounty than the person they defeated, however jinbe who was a schikibukai got a bounty of 1.1 billion not because he defeated whoswho (the cp0 already expected that) but because he was a warlord