But by that logic, couldn't a char with 100/25 switch to Hero, die the next day, and be buried as a Legend? That doesn't seem very Legendary.
That is why I think there is a number that must be accumulated while they are actually a Hero.
I have seen characters change class to hero, then die within no more than a few days, and be hailed as a legend. It's long enough ago that I don't recall the specifics, but I remember it being talked about at the time specifically in the context of the Legendary Hero fame.