Great article on NASailor.com with the great Gary Jobson on the future of the sport and what US Sailing is doing.
There is common theme with Nicholas Hayes' Saving Sailing. We have a donut problem. There is little shortage of teens and college kids who are actively sailing. There is certainly no shortage of middle aged and older folks. The problem is that we have a hole in the middle as the sport loses people aged 25-35.
From my own experience, there are too many competing demands. It's the time when you're getting married, having kids, buying houses and building your career. Sailing takes a lot of time. Even golf only takes half a day. Taking part in a regatta, maintaining a boat, improving your skills are huge time commitments at a stage of life when you have the least to spare.