I think part of Souths biggest problem was their first season back. The recruitment for that team was completely and utterly diabolical. They signed a bunch of hacks, and thus, it has continued. Once you set a culture in motion, generally it continues.
You look at the halves they have now, Williams - nothing, Walker - nothing, Sutton can be devastating at six but gets no support from the number 7. Its been like that since their reintroduction.
Basically they seem to have either recruited borderline reserve graders, over the hill donkeys, or toilers and nothing more. Players like Chris Caruana, Anthony Colella, Owen Craigie, Jamie Fitzgerald, Glenn Grief, Andrew Hinson, Andrew King, Duncan McGilvary, Scott McLean, Paul McNicholas, Blainey Stanley, Zane Clarke, Stacey Katu, Damien Mostyn and Joven Clarke were terrible purchases for season 2002. None of them offered anything. None of them. Not one of them.
However, was this because they entered the player market well after all the other teams? If it was, its understandable, but is still largely the reason in my book they've fallen by the wayside - along with infamous decisions like 3 year contracts to unproven coaches on the basis of a close loss.