They would also need the clientele that can actually afford to pay for it as well. Unfortunately NCL and the NE is still pretty much the poorest area in the UK. But, near enough 70% loads year round is not too bad (though not great as VV points out).
Growth will continue though so it's not all doom and gloom.
FWIW, CDG seems to be doing extremely well, as well as AMS. Still plenty of room for growth on CPH, BRU and DUS though.