That’s very nice but some of them must have died young if they were all Kohanim Gedolim and there can only be one at a time….
Your premise is incorrect. While there is generally only one *active* Kohen Gadol at a time, there can be multiple people at the same time who have the status of Kohen Gadol.
Example: Anyone who served as a substitute KG, still has the status of KG, even after the regular KG resumes his duties.
In addition, it’s entirely plausible that they all lived long lives, but most had short tenures as KG. (i.e. the eldest brother was KG, died at 80 and his younger brother took up the role at age 78. He had it for three years until he died and then his younger brother took it…)
The Wolf