Locally (in the ACT) the problem is in numbers. *back in my day* we took away a squad of about 25 bowlers for nationals including the shield team, and most of them were 15+. Most of my team this year is younger, much younger, and the fringe players I have are young too. This is due to a decline in the popularity of the sport in general as well as a lack of effort on the part of all involved from the state association (which I am the president of, I'm not slinging at anybody here), the centres, and the bowlers too in keeping numbers up. AMF have allowed junior leagues to dwindle. ACTTBA allowed AMF to allow the junior leagues to dwindle. The bowlers, their parents, their coaches etc etc aren't doing anything to add any interest in the sport.
Times are changing here though, watch out for the ACT in a few years!