Look at other enriching activities, such as skateboarding, skiing, tennis, etc.. People might take initial classes to get them started, but after that they're left to their own devices. Of course, being around people who are more "advanced" (there's that word) can certainly help them learn. But most of their participation is on their own time, and they freely enjoy the activity, and progress as they go along.
Dan, are you speaking from an extensive background in skateboarding, skiing, tennis and et cetera? How do you know that people in these activities are "left to their own devices"? For that matter, how do you know that they don't have ranking systems?