Go back and read what I said.
I said pirates bounties are is based off their threat level. A pirate can have a higher bounty than another but still be weaker than the pirate with the lower bounty. Typically bounties are based off of multiple factors.
Mihawk having a high bounty than Hancock means the world government consider him a greater threat than Hancock even though she is a captain, has her own crew and territory.
You are confusing swordmanship with sword skill. Swordsmanship is your fighting style and sword skill is your fighting strength.
Even though the Scabbards used Oden's swordsmanship, they failed to even reopen Kaido's old wound because there's sword skill weren't on Oden's level. Kaido stated their sword skill doesn't resemble Oden's.