WB was the WSM
Roger was the King of Pirates
WB was as strong as Roger
Roger died, WB take the reputation of "King of the seas"
Almost every pirates wanted to be the next King of Pirates
So, basicallly, they needed to be, at least, equals to WB, the WSM, the only man that could go toe toe with the previous King
We can say that millions of pirates wanted the title of WB
We can say that WB had millions of enemies but no one as strong as Roger so no rivals
Regarding Kaido, the WSC is a no-sense title
Regarding Mihawk, even among the strongest swordsmen, like Shanks, no one have interst in his title, only Zoro
WSM is the most important title after PK
WSS and WSC are lazy writing, the WSC even more than the WSS (Kaido never had a rival as strong as Shanks lol)
Roger was the King of Pirates
WB was as strong as Roger
Roger died, WB take the reputation of "King of the seas"
Almost every pirates wanted to be the next King of Pirates
So, basicallly, they needed to be, at least, equals to WB, the WSM, the only man that could go toe toe with the previous King
We can say that millions of pirates wanted the title of WB
We can say that WB had millions of enemies but no one as strong as Roger so no rivals
Regarding Kaido, the WSC is a no-sense title
Regarding Mihawk, even among the strongest swordsmen, like Shanks, no one have interst in his title, only Zoro
WSM is the most important title after PK
WSS and WSC are lazy writing, the WSC even more than the WSS (Kaido never had a rival as strong as Shanks lol)
Roger achieved his title because, yes he was strong (not the strongest since Rocks, WB and Garp were arguably as strong if not stronger) but he also had a crew, had allies, and was lucky af.
Now another character that proves Yonko doesn't require strength to attain, is Buggy the M*****F***ing Clown...nuff said
WS titles though only require, as the S in WS suggests, strength. You absolutely have to be the strongest to be called that; such comon sense right? yet here we are!
In reality the real problem is the definition that people have of a swordsman, some agenda driven and some genuinely(I guess :s), believe that to be a swordsman one has to somehow say it out loud or not use anything but swords, basically Zoro or Mihawk; whereas it was mentionned numerous times that anyone wielding a blade is a swordsman, technique will ofc help eliminate the fodder but in the end the strongest will prevail; ''I will win even if I have to use my teeth'' said a certain famous swordman.