I believe it is also the fault of the airlines, in part, for directing resources elsewhere. When it comes to NCL they all seem to jump on the same bucket and spade routes, which really does little good for anyone.
Ryanair appear to be having positive results by going against the grain and offering Warsaw, Gdansk, Wroclaw and Madrid. EasyJet appear to be doing well to Berlin, Jet2's charters do well, but (except Ryanair, of late) they're all very slow to commit long term. i.e I'm sure NCL-VIE could e a success with Jet2. Budapest, Munich, Milan, Venice, Hamburg, Lisbon, Athens with EZY/FR/EW/W6