My theory for what will get Ippo out of retirement (spoilers)
I just reread the whole manga and caught up to the latest chapters, and now I have a theory for what will get ippo out of retirement. I think one of the characters is going to die. I think what will happen is a character will die and that will motivate ippo to become a monster and finally walk across the line Takamura made by the tree. As for what character will die, I have no idea, but it could be Mashiba, which could lead ippo to feel like he wants to become world champ to fulfill Mashibas dream that he failed to acheive. Or maybe sendo will bring out Ricardo’s true power in their fight and Ricardo will accidentally kill sendo and that will drive Ippo to challenge Ricardo to avenge his friends death. Or maybe his mom might die somehow and he gives up on the family business and goes back to boxing, I know he weighs is mom as more important to him than his love for boxing but if she died that could change. All I know is he won’t come out of retirement unless something really big gets him too and I think a character death is the only thing impactful enough to accomplish that and turn him into a monster that can challenge the world like Takamura.