When the young guys don't join, that's what you're left with.
I do think, though, that the drop in membership just reflects the fact that people don't join clubs in general anymore. You see the same aging membership in the Rotary, the Kiwanis, the Lions Club, the Moose, the Elks etc..
I think they are all destined to die out, which is really a shame, but, then, I never joined any of them, either.
One more thing. Most of these groups had a substantial charitable purpose. A lot, if not all, of that has been taken over by the government. Younger people see less and less reason to volunteer for charitable purposes. They figure it will be taken care of through their taxes.