>>40109168Except it's not the bloody same. The kahuna are basically gym leaders with the whole grand trial thing. Two don't get bumped up to the Elite Four until much later and even then Kukui took two randoms as well. Not to mention they're shown with a different set-up anyway. They basically pulled a Koga.
In the anime the kahuna aren't Elite Four tier, just at most gym leader tier and it gets shown. Them being the strongest on the island when they get shown to be challenged as effectively island gym leaders just says they aren't all that strong in general. They aren't the Elite Four either because there is no Elite Four. Z-crystals are obtained by either the kahuna or randomly through other actions or locations. Badges are obtained from gym leaders and you don't just find those lying anywhere either.