Keeping young kids involved in something as physically demanding and difficult as wrestling can be, IMO is about having a certain amount of success early on. This is not a universal truth or anything, but it's a pretty good predictor. The more success kids have early on, the quicker they begin to self-identify as a wrestler. When a kid begins to identify with the sport, when he says internally "I'm a wrestler", he's hooked. Developing his skill-set and competing becomes intrinsically valuable to him.
Having said that... defense defense defense position position position
Most youth coaches teach kids too many "moves" and to "be aggressive" while neglecting position, motion, defense and set-up action. With that in mind, you know the majority of your opponents will be coming at you over-aggressively with sloppy leg attacks. Good position, reaction timing and sound defensive technique translates in to wins in the early years.
A focus on position/defense = early success = self-identification = athlete retention/numbers.