I dunno this my be off the wall but I have a theory that most young men are put off riding for life when they express an interest in riding and their girlfriend decides to “teach” them. On her horse. Her 3 year old. Off the track. 17.3hh. Stallion. Or her barrel horse. Or throws him up on a borrowed warmblood because it’s quiet, unfortunately it has a 16 foot trot stride and likes to chase dogs (OK OK I did that, but it wasn’t actually a warmblood and I NEVER would have taken the four dogs on the trail ride had I known, especially through the big meadow, and he was a sport about it once we caught up with him ). And then decides he really should jump something, just a little thing, so he gets to see how much fun it is right away… Etc. etc.
This theory is based on data collected in college mostly through my roomates and friends and a series of unfortunate young men they tried to maim- But I have seen it happen with high school kids too. No wonder they all quit…