I can say from my perspective as a 21yr old flight instructor that there are quite few young students learning how to fly. However, I think a lot of them are pushed into it by their parents. I once did an intro ride for an 8yr old whose father set up the whole thing. The kid hardly seemed interested. As for fewer young people learning to fly, I cannot say thats all bad, because less pilots to fly the planes equals more demand with less supply and maybe higher salaries for those who stuck with it in the future.