One thing that is an eye opener for me in this forum is the amount of talk of the younger age groups 13 & 14 in particular. I understand this is a GPS forum, however about a good third or more of the conversation is about them. I think it's great to see these young kids develop, but there is a long way for these kids to go before they are in the 1st XV.
Given that the 15s is constantly interrupted by things like immersion, and the 16s act like a reserve grade for the firsts, the 15A and 16A competitions don't carry much weight. This is probably why you hear more about 13s and 14s (and some 11s and 12s now that they play the GPS schools). You would hear about the 15s and 16s otherwise.
School's are also pushing a more "whole of school" approach. Churchie and Terrace both introduced this approach this year, and of course you had the the whole of school trophy between Nudgee and Terrace for the first time.
You also have a large state program in the lower age groups as well, which makes a lot of folks interested in the junoir programs.
On the last point however, really playing well in a first XV starts as young as the 14s. You need to develop a lot of skills, and slowly build to a good level of fitness and strength from a young age to excell now. So the journey really starts in grade 9 for anyone aspiring to be a force in the firsts.
Take the 13 for GT's 14As... He is in grade 8, but his age pushes him up to the 14s. When he is in grade 10, he will be playing firsts giving him potentially three years. In two years time look for him on the wing, and then at 13, he is going to be a match winner and his journey started this year in the 14s.