Being an Eels fan there is some experience at the problem.
Basically it goes to clubs giving out 4/5 impressively large contracts to players over a decent term and as they decline, the team can’t adequately enter the market to replace them. Manly show how that happens, Bulldogs too, Broncos seemingly paid overs for young players who lack experience and the Cowboys like the Dogs invested in players not in the positions that provide the foundation of a competitive roster.
Coaches can’t turn those sort of rosters around in a couple of years, so as they restructure they have a couple of seasons of poor results. In Sydney the Panthers and Eels are doing a better job of identifying good juniors and aren’t losing them in numbers that helped other teams.
Seems that it rears its head about the gap when teams mentioned who have been the ones on top are experiencing the life of being on the other end of competitiveness. It’s a game that sees these shifts, just different clubs currently, it will move around and the names will change again.