Don't know, but caving is not a sport/activity that is going to attract huge amount of numbers in the first place, and taking/guiding young persons is tied up in red tape, basically covering your arse, so lot of cavers are not going to make the effort, and you can not really blame them, + I think todays society also plays a role in this as well, choice of TV stations available, computors and computor games, a lot of young people know nothing else and apart from swimming and football, which obviously will vary across the country, most other youth activities struggle for numbers. I have heard, and do not know if true, in france the school sports/activity curriculem covers the local area major activity, so in a caving region they would cover this and if you have ever been down pucelle it does seem to have children in it most days, although this only an observation based on the 2 times I have been down that way.