I've thrown this idea around before, but it's possible aveverage bounty plays a signficant factor based on crew size.
Let's factor in all "6" Yonko (those previously called or currently are considered it). First, let's separate them by 2 categories:
- Armies: Whitebeard, Big Mom and Kaido
- Powerful individuals: Strawhats, Red Hair, Blackbeard
Now of course the "Armies" category have powerful individuals, but the average bounty of said powerful individuals could potentially be higher than average.
Let's remove Blackbeard and Strawhats then, because at this time, we do not have much to go on here when it comes their bounties since they are still growing in strength. Focusing on the armies, you seem to have:
Big Mom: 4.38 Billion
Kaido: 4.611 Billion
Whitebeard: 5.046 Billion
Their YCs:
- Katakuri: 1.057 Billion
- Smoothie: 938 million
- Cracker 860 million
- King: Unknown, but probably 1.32-1.5 Billion (under Luffy's, over Queen's)
- Queen: 1.32 Billion
- Jack: 1 Billion
- Marco: 1.37 Billion
- Joz: Unknown
- Vista: Unknown
Since Izo's was close to Ace's (510 million vs 500 million), it's safe to say Joz and Vista are the representative top 3 with Marco. I'd assume they are both Billion bounty pirates as well, rivaling Kaido's.
Big Mom would then seem to be the weakest average Yonko by virtue of her commanders. While we know a ton of her veteran bounties, we don't know the F6 members to make a decent comparison, since we only have Basil and Apoo's bounties to go off of and even they may defect. Kaido would then seem to be roughly the 2nd "weakest", since Whitebeard edges out Kaido, but we dont know what Kings bounty is to compare to Marco. What we can confirm is that Katakuri is probably the lowest bounty top commander
All in all, they are probably going to be on the "weaker" side of average bounties. After this arc, it seems the 3 "Powerful Individual" crews are what is left. Luffy and Blackbeard are still growing, and if Luffy defeats Kaido, his bounty will probably rival his or somewhere around it. What may get factored is the 20 other people who fought Kaido and damaged him lol, so Luffy's bounty c ould be lower than 4.6 Billion, or maybe it won't. Zoro and Sanji will probably defeat Queen and King, so they may rival Luffy's current bounty.
Mihawk probably is anywhere from 3-4 Billion. And if he allies with Shanks it would be commensurate with Shanks's likely crew bounty average (1-2 billion) outside of his top, which I'd expect Beckman (possibly Sanji's opponent) and Roo to be similar/less than Mihawk's (over 2 billion, under 3.5).
Blackbeard is interesting cause like Luffy he's also growing. We won't know his final bounty for a while, but I'd assume similar or slightly less average than Shanks (as a crew; blackbeard himself may top Whitebeard's but not Roger, symbolically that may be Luffy unless Dragon legit is the world's most wanted man bounty wise)