Considering Newcastle spent £50m in the summer and were supposed to walk away with the league, they've been pretty underwhelming this season.
No question they've been underwhelming.
Unfortunately, promotion is really the only thing that matters to them. As soon as they're back in the PL, they leapfrog nearly half of the league in terms of what they can spend on players and that gives them a massive advantage w/r/t avoiding the trap door. It's taken a real masterclass from Mike Ashley to see them relegated twice in the past ten years given the budgetary advantages they have over most English clubs. If he can manage to employ a competent manager (which, sadly, Benitez is) for an extended period of time, they're going to be a PL team.
The good news is that if Ashley gets bored with Benitez, there's a real chance he does something disastrous. Kinnear > Hughton > Shearer > Hughton > Pardew > Carver > McLaren is a run of appointments that even Sunderland might sneer at.