The biggest problem is that SA and WA don't have anything focussed on developing kids.The problem is different rules for different states. NSW and QLD having academies, Victoria providing the glut of juniors whilst SA and WA wither away with minimal help.
Victoria has the Talent League, where the entire focus is the U/18 players that'll be drafted in the next two years.
NSW and Queensland has the Academies.
In SA and WA, we've got the SANFL and the WAFL clubs. State League Clubs that focussed on winning senior flags in their local bush leagues rather than developing 16 and 17 year olds that may play some games for them in one year before being drafted to the AFL.