It's possible everyone's posting here is correct, but not the complete explanation. Nor will I claim to have the answer, but another piece of the puzzle. One may be that these days with many new and different recreational options available, sailing's slice of the pie has grown smaller with the competition from other activities.
Another piece may be what my inexperienced impression of sailing was - boring. Boring compared to PWCs, wakeboarding, windsurfing, and now kitesurfing (which is replacing windsurfing). Boring until someone took me out for my first time on a sailboat, which happened to be a Hobie 16, and got me hooked within 15 minutes. My in-laws are all sailors on monohulls, and didn't understand my need to get a cat until I bought one and took them for a ride. Now they get it.
Too complicated. An inexperienced eye looking at a sailboat is put off by all the lines and wires, not to mention having to know how to get the boat to move while being at the mercy of the wind.
There's no doubt we now have 'many new and different recreational options available' but as I see it, and much of what you say is indicative, there is very little being done to encourage and/or sell sailing to younger people, particularly cat sailing/racing. There seems to be plenty of money to build bigger and faster boats in ever more diverse classes for the cashed up minority but there's not much money around for youth training.
One of the problems sailing has selling itself to prospective participants is the difficulties of televising regattas. Unlike football, golf, basket ball etc, we don't have regular television broadcasts of sailing. The mechanics and environment are such that making an epic video which Joe Average can relate to, is very difficult. Technically it's difficult and it is seen as complicated and there are no good commentators with sufficient knowledge to adequately explain what's is going on. It's been done but not well IMHO. Mostly these telecasts only cater to the sailing-wise. It could be done so much better and considering there is a huge amount of advertising space on a set of sails, it's got to be lucrative. The commentator/s is/are the key. I remember the Sydney Olympics and the pathetic and often blatantly derogatory commentary that went with the sailing telecasts here in Oz. It was a bloody embarrassment to anyone watching with any knowledge at all of sailing. An absolute disgrace.
It would seem to me that some good money needs to be directed toward educating the public, training youth to sail, and finding some good sailing commentators.