I think juniors are definitely the future of archery. One of the main problems at the moment is that archery (in this country anyway) isn't seen as a "cool" sport do pursue.
The most important reason for targeting young people for archery (pardon the pun) is that they are still easily adaptable, with not yet fully developed muscles, and usually have parents who are willing to spend money on them for a sport. By trying with lots of juniors, they're sure to get a couple who really enjoy it, are great at it and are able to make it all the way, with prospects of a long career ahead of them.
If it were all about increasing
GNAS numbers just for the sake of increasing
GNAS numbers, sure, target older people with more time and money. But it certainly won't help raise the profile of the sport in the public eye, which is what
GNAS is trying to do by recruiting juniors.