Mostly there are people who enjoy sailing but can't or won't do it often enough to be interested in knowing the RRS. In addition they mostly seem afraid of embarrassing themselves, being in the way of someone screaming and so on. At the end all they do is reach around, capsize a bit, bring the kids or a friend for a couple hours on the water.
Then there are people who do all the RYA training courses, obviously enjoy it, but don't jump the gap and join the racing. This is due to the gap between the RYA training done at the club on Topaz/Vibe/Dart/Hobie and the racing where none of those classes are represented. They put on some "begin racing" courses but not one person registered for those...
Finding the magical tricks to get those two group of people to race is tricky.
So we have a number of initiatives, ranging from getting people into racing via crewing first with an established racer, special loaner boat only for racing or "fun" races with mostly beginners where we spend time explaining the rules and flags