One way to even up the comp might be to realocate the junior areas as fairly as possible, giving each club a fair share of the junior nursery area.
Under this system juniors who come through the clubs system are that club's "property" if they want to play for another club then the club of their choice would have to fairly compensate the club who developed them.
I realise it would not be easy to re allocate the nursery areas in Sydney, but it could be done by giving some or each club a share of the NSW or QLD Country areas.
One down side is that apart from (Politis) of course, is that the NRL does not appear to be overly concerned with Junior development, and some clubs are to cash strapped to be able to contribute to the development of juniors in their allocated area.