When most of us were younger you literally had to make your own entertainment rather than buy it and modelling was a major leisure interest for younsters growing up in the 50s & 60s. As Dave says, there was a huge club and association infrastructure to encourage and support various branches of modelling and lots of opportunities for competition, even for scale boats once proportional R/C became widely available.
Youngsters naturally gravitate towards fast noisy things and probably get most of what they want these days from video games. What is lost however is the satisfaction and pride that comes from being able to say 'I made that' as opposed to literally dancing to somebody else's tune.
I have always been interested in boats of the scale variety myself since primary school although, like most people of my generation I dabbled in other branches of the hobby. With aeromodelling I quickly discovered that what goes up will inevitably come down and frequently either in bits; over the horizon and never to be found or, on one notable occasion, in flames due to an incorrectly mounted Jetex motor. I found that boats, which usually stayed in one piece after you had made them, to be a more satisfying option.
So, these days, model boaters are largely comprised of retirees returning to the hobby or refugees from other areas of modelling looking for a quieter life and of course age does tend to bring patience with it although, for some obscure reason, this never seems to apply to painting!
Colin