In the end it will come down to UA deciding if they can make more money with that 757 elsewhere or whether they are happy with the returns they are getting flying it between NCL and EWR.
I suspect loads will need to be higher than 60% to see it return next year. I hope UA maintain the link though.
BA had a saying when they operated the 767 to JFK from BHX. 'Use it or loose it.' In the end we know what happened there. Bristol is another example of the then Continental flight to Newark being axed. It wasn't sustainable.
I hope councils and the tourism industries in the region can get together and spend some money and time on promoting the route or else it will be curtains.