The Knights of the Round Circle has been training kids at several events for at least ten years. Lots of happy kids, no new members....ever!
And that includes the STEM Fair and AMA expo, both of which should have SOME interest in continuing.
That was exactly our experience. The problem is that we are expecting a result that will never be forthcoming. What you guys are doing is great PR. That's why they want you back. You need to
do something different if you want to generate pilots.
Again:
Flying with the kids is a good point-getter if you are trying to protect or acquire a flying field but it doesn't turn kids into modelers. It is extremely useful as a PR tool if done well. But it doesn't generate modelers. It does generate good will.
Modeling turns kids into modelers. Until control line people understand that, we won't see growth. Flying someone on a trainer represents entertainment. And it is in competition with all kinds of other (and often, more fun) entertainment. If the child BUILDS the plane, flying becomes more than just entertainment, it becomes achievement and accomplishment and self-satisfaction.
Run a building program and then help the kids fly their planes. See if that doesn't do it for you. I'm not saying it will be easy. You are fighting culture.