They don't have the incentive to ruin people's lives to game their performance metrics (like prosecutors do). They don't have incentive to make much to do over nothing to justify their budget (like cops do). They don't have incentive to keep people in the system as long as possible to milk money from them and the state (like the prison system does). They don't have incentive to perpetuate the war on drugs to sell crap we don't need like tasers (police abuse them) and post-release monitoring (an overpriced joke that plays fast and loose with people's lives).

The bad incentive for judges seems to be that most of them have a desire to not rock the boat too much which is pretty benign compared to all the other actors who go out of their way to perpetuate and further the status quo because they materially benefit from it.

I find it hard to fault the judges for apathetically presiding over a flawed system when every other group you mentioned is doubling down to further that system.