TomNamikaze
TomPen94, Banido
In Bulbapedia, All exept Pryce have been already appeared in magazine chapter. It could be another hint that he is very crucial in the plot(And yet it is only a hint). If he didn't who would become the Mahogany Gym Leader? He doesn't have anyone who has close relationship with him. And I don't think Lorelei would replace him
There is just no one to replace him. Kusaka shouldn't have done that with him. If the games had replaced him, then there would be a successor, but he wasn't replaced in the games, and as so there is no one to take the Mahogany Gym Leader place.