Whitebeard, on panel, was called by Sengoku a man with the power to destroy the world. Coincidentally, the World's Strongest Subordinate wanted to test himself against this man to measure the distance between them and that attack got intercepted by a subordinate. It wasn't even worth that Yonko's time.
No, I exclude Buggy because he is a gag, he isn't an actual Yonko in the same way he wasn't an actual Warlord, and I wouldn't have held his lack of strength against Mihawk when they were colleagues as Warlords, if you care to remember.
To remind you, because you so conveniently forgot, three of those four Yonko have a lesser bounty than him because they only recently came into power. Blackbeard purposely kept his head down for decades to go unnoticed. Buggy accidentally found his way to success after meeting Luffy only two years ago, and Luffy only recently started his journey. In terms of feats, two of the aforementioned three, and Law and Kid, have done far more than Mihawk has in his decades long career. Its only recency that gives them a smaller bounty.