Oda is going senile with bounties.
The most likely explanation is that he just don't give a fuck and uses bounties that he thinks are worth at the time and them updates according without caring about how it affects the world.
So he gives a bounty to Sabo that is comparable to Doffly but shows that Doffly is stronger. Ok.
Jack appears and he gives him a 1B bounty to show that Jack is in the high leagues.
Kata shows up and he must be hyped so he gives a bounty better than Jack.
Kaido has to have a good crew so he gives better bounties than kata to show the power of the crew.
The Yonkos have bounties that are super huge (except BB because he is a novice) so he picks 4b for the group.
Now he needs to hype Mihawk after his pathetic showing in Marineford and he gives a bounty that is high but not close to the Yonkos.
Now, when we see Sabo again he will have a proper bounty and the same will be done for the rest of the revos.
Inflation and poor planning. Is a waste of time thinking about reasons for bounties besides ''it's cool''. They only help with power levels of the current arc at best.
The most likely explanation is that he just don't give a fuck and uses bounties that he thinks are worth at the time and them updates according without caring about how it affects the world.
So he gives a bounty to Sabo that is comparable to Doffly but shows that Doffly is stronger. Ok.
Jack appears and he gives him a 1B bounty to show that Jack is in the high leagues.
Kata shows up and he must be hyped so he gives a bounty better than Jack.
Kaido has to have a good crew so he gives better bounties than kata to show the power of the crew.
The Yonkos have bounties that are super huge (except BB because he is a novice) so he picks 4b for the group.
Now he needs to hype Mihawk after his pathetic showing in Marineford and he gives a bounty that is high but not close to the Yonkos.
Now, when we see Sabo again he will have a proper bounty and the same will be done for the rest of the revos.
Inflation and poor planning. Is a waste of time thinking about reasons for bounties besides ''it's cool''. They only help with power levels of the current arc at best.