It seems like it's only a problem around top-tier players (i.e. genuine first graders likely earning $400K+)
I don't believe a single club wants those players to be performing below their contracted value, and if they're earning at or above that value then it's unlikely that the club doesn't want them playing in the 17.
It's also difficult to shift a player that is underperforming or has been relegated to Reserve grade.
E.g. Russel Packer or Josh Reynolds for example. Those players may be (reported to be) somewhat shopped around, but at the end of the day it's up to the player to want to shift, and often the clubs end up subsidising the players salary to play at another club. That's an unwanted hit for the club and fans.
I struggle to think of many examples where a player has been "done-over" by a club. The only one that springs to mind is where there's a real falling out between Coach and Player (e.g. Robbie Farah vs Jason Taylor) - that seems like a pretty rare circumstance and one where both parties ended up losing.
Seems to me that players & player agents typically have more power than clubs when it comes to contracts - they can shift when they're playing over their contracted value, but stick around and claim their contracted value when they're playing far below it. Look at how much power Joseph Suaalii seemed to have despite being 17 and untested at NRL level...