Personally I don’t agree that a lack of visible accountability is a problem. There’s accountability, it just exists behind closed doors. It doesn’t come in the form of being fined for making bad calls. My source on both of those is being directly informed of each by a former NHL official (Wayne Bonnet if you want to look him up, he worked as an NHL linesman for 10 seasons and helped out with working with officials in Arizona during my time as an official there).
We do get to see at least some of the accountability in terms of who gets selected to work the playoffs and who makes the cut for later rounds. They get bonus pay per round they get selected for so there’s motivation for it.
As for their accountability ever becoming public, well, the officials have a union too and would never agree to it. I spun it would be very high on the league’s list of things to try to negotiate with the NHLOA on either.