Hey Mark,
I'm not sure what you mean when you "these boats will leave the dock and go somewhere" - most just take a noodle run around the River or Bay and return. Some go to spots to anchor for the day or night, but most go for a sail and come back, pretty much like what I do with my cat when I day sail. Maybe you mean lots of trips back and forth to the beach, whereas the marina boats go for a while and come back, not sure. Not sure if that's really a diff.
I may be the odd one - I never lost interest in going out for a sail with my folks as a kid. We'd pack up some food and head down the boat and spend the day sailing around the Bay. Never anchored, never went overnight. But usually started mid-day and came back late. The only complaint would come from my Mother when my Dad, Brother, and myself insisted that burying the lee rail was the only fun way to go upwind! Light air days were boring, but we were still where we wanted to be. And my brother and I were into sports and all the usual stuff, so we had distractions.
I'll agree that for turning youngsters loose on the water in something age-appropriate is good. And I am a strong advocate of having as many boats as you can (don't make me count...), just because you should. Growing up, in summer time we had a small skiff and other stuff to use, and we made use of them (catch minnows, sell to bait store, buy gas for outboard...), none required a yacht club. The family outings are what stick in my mind - the times we kept the boat in fancy facilities with all the trim none of that stuff ever got used - if we were there we went sailing and nobody got left/stayed behind, so the extra money was wasted.
So, again, have lots of toys - but when you do, one or the other will take priority. And if costs as much to store/use a more limited toy as it does a bigger one, guess which one will lose in my house. But again, different situations call for different things, so I still say both are relevent. And I don't believe fancy facilities are a requirement for all of us.
Now, again, if PPYC wants more cats, I would suggest they offer a reasonable monthly or seasonal (not a yearly commitment) beach rent deal, with the pool and tennis as optional (not required) extras. Then advertise it. I'll bet they'd have success, and people could option up or down according to lifestyle and budget. I would even consider it. By the way, the last time I was at PPYC a lot of the beach cats didn't look like they were getting the use your argument would support, but appearances could be deceiving.