Well, I am 28. I started sailing cats and some dingy's when I was 13 at the same beach I still call home. 15 years later, I am the second youngest sailor on the beach most weekends. I went to college and grad. school.
From my perspective, there are 4 pretty good reasons there are not more "young" sailors:
1. I travel to Australia for work from time to time and have found that the US takes "careers" much more seriously. The goals most college students have relate to a future career success, not really future lifestyle success. Many are focused on getting a management job and status symbols. I say work to live, not live to work. Success isn't the corner office. Success is getting a company to bankroll my life... ha ha ha.
2. Unbelievably horrid marketing on the part of beachcat mfg's and dealers. I take a lot of first-timers sailing every summer and the majority are so suprised how fun it is and that they could get a cat for less than $2000 for recreation. What the heck happened to the "Hobie Lifestyle". Why does Nacra's website look like a 12yr old made it? Geeezzz... come on. They both have great products!
3. Mediocre racing classes. I have always been of the mindset that if you want to run a race, you go by boat size, not make/model. Divide the race up into >17' and <17.1' and keep it open to all types of boats. The guys that are serious about racing will have the latest and greatest stuff. The people that are out for fun will do their thing and most will get out of the way of the serious people. Toss out those boat ratings. Toss out the standard race course. Do something inventive.
4. Sailing is a lifestyle. It is spiritual. To lump it in with football and baseball is really dumb to me. It is up to us as seasoned sailors to convey that message every chance we get. Wind may make the boat go forward, but sailors make the lifestyle go forward.