So again to sum it up:
Luffy - works his bounty to 3 billion, defeats several warlords with Crocodile being first one, who was also crushed by WB, Lucci, Impel down, Marineford, defeats two Commanders of a Yonko, Grand Fleet, defeats Kaido - 3 billion, cool
Crocodile - crushed by WB, defeated by Luffy, fast forward off screen and now he would have had a bounty higher than Luffy's if the Navy didn't mistake Buggy as the leader
I wanna know what mushrooms is Oda eating, better be some damn good reason beyond just putting a bounty on a marine