I’ve been doing a bit more thinking on this. Just for reference, I’m 25.
People my age tend to be doing lots of different things, for short periods of time, rather than one thing for a lot of time. In the words of the experts, my generation is very ‘time poor’. I know some oldies will say that is because our generation has a very short attention span, but while that’s partially true, it’s mostly a result of having FAR more opportunities available to us. Therefore to get it all in we have to spend less time doing each thing. Modelling really doesn’t play into that, although it does explain why RTRs are more popular.
Furthermore, where kids used to walk down to the local park after school for the whole afternoon, the ready availability of cars in families mean that parents take their kids to things which are further away and more specific - for example football or swimming classes, and aren’t as keen to have their kids walking around unattended any more. So the experience of being a young’un taking your model down to the lake to show your friends isn’t really feasible any more.
I think modelling is evolving though, with 3D printing and more interesting electronics (like arduinos etc), it’s gaining a newer appeal to the younger generation.