Your group sounds sort of like mine and the age battle. Then there are the kids who had inherited the farm equipment or bought from a previous member who passed away. BUT, they are starting out new, raising a family and have day jobs.
The best folks to pick to moderate are wise enough not to get picked or will turn it down.
My membership community resides on 4 continents too.
Making the move from YG to GIO, the membership numbers adjusted like a landslide. Sure, we have history, yet the participants are now up to 35 years older from the startup. The re-enlisted is a mix-bag.
So, it would require some time, possible a year before prompting folks to step up.