As a person who has been involved with dogs for 10 years and being being 31 years old, I think the second problem you present is sweeping generalization that couldn't be more false. 1/2 of the people that were in the retriever club when I joined were, just like me, still in college. And all trained their own dog. In fact, I only know one person under 30 that has ever sent their dog to a pro. Most of the folks under 30 don't have enough disposable income to be able to pay a pro. Throw in a couple kids with day care/ pre-school expenses and a lot can't afford a well bred dog and training equipment, thus they have to join clubs and partners.
When I got into the dog world, I was very blessed to have very experience handlers and trainers in East Texas that wanted to share their time and knowledge with a rookie like me. Those men and women, along with a handful of judges, are what made me want to continue to pursue the hunt tests. AWESOME PEOPLE. In my continued pursuit, I found what they had really been teaching me and why the majority of us play this game; the bond that truly represents a man and his best friend.
We all know how much time and money it takes to train a dog to properly compete in hunt test or field trials. I remember how frustrating it was not to know people who would let me use their land, not to have enough money to buy training equipment or videos and not having the knowledge to make sure I wasn't "messing" my dog up. But I wanted to learn and would throw birds, plant blinds, load wingers, etc. all day just to make sure I would get invited back. Thankfully, I did.
By the time I had the knowledge and was making enough money to buy those things and new the people that would let me use their ground, I was working 40,50, 60 hours a week and didn't have the time I had when I was in college...Then I had a kid...then another one...
My point to this is, we've got to make sure that we're doing our fair share of recruiting and getting the word out to folks that can move our hobby/sport in the right direction. Make sure we go out of the way to welcome the folks at the Junior/Senior level and see how we can help. This is a tough sport to get youth involved in and keep them involved because if the parent isn't involved and will allow dogs, then the kid is just SOL. Plus how many kids do we know that would rather spend the weekend with a bunch of adults and dogs instead of their friends at a baseball or basketball tournament...or chasing girls/boys?
A wise man once told me, "So you want to get into retrievers, huh? You might want to look into cocaine. It's a cheaper habit and for the most part, the women are hotter."
I don't think we can pinpoint why the numbers are down. I know when I was running junior and senior tests, I wouldn't even consider running a test unless they had double junior/senior tests offered. I'm not going to wake up at 4 a.m. and drive 4 hours one way, spend $60 to enter and $200 in fuel for one $3.50 ribbon, but I would for two... I got the same thrill training 10 minutes from the house. The real thrill for me was cold December and January mornings...
The junior and senior level tests were great for my experience as a handler. I'm convinced my dog never failed a test; I'm the one that failed. He could do the work, but I was the one that crapped the bed. That being said, I don't know that I'd run those levels again with my second dog that is now 15 weeks old. I'm much more confident in my ability as a trainer and handler now than I was then. I don't know that I see the benefit in it for us at this point.