I've always thought its about the dominance of the fowards, or lack of dominance of our forwards.
If you look at Melbourne and Roosters premierships, our current backline easily matches up to those lineups, but our fowards don't. Cook went missing in those 3 PF, Sam was busted in the first, and we haven't had an equivalent replacement for the other 2, the front row doesn't compare to Melbourne, only Murray is the stand-out. Arrow was Sam's replacement but he is hardly comparable, Sua disappeared in those last 2 PF, and disappears against every really big forward pack, Tatola is hardly the definition of "dominant" forward, Knight was only good when his contract was up waiting to be renewed, Cartwright is garbage, there's just no comparison. Even if you compare our pack in 2014 to the packs that made up the last 3 PF, the 2014 pack is way above the others.
The problem has never been Reynolds or Cody or the backs, it's the fowards and lack of dominance compared to those other teams.