Pretty sure it was stated that Nunh rarely become leaders, and I think this includes leaders in combat. Even though the Nunh is the strongest of the tribe, I doubt they'd put their best breeding male in any sort of danger. Perhaps one of the perks of being a Nunh is that you don't have to risk yourself as often, but it also means others tend to surpass you because they aren't sitting around. After a couple of years or so the Nunh is challenged and overcome, resulting in a healthy rotation of breeding males.