Small catchment area, half of which is in the sea and another third of which is inhabited by sheep.
A relatively 'poor' (by the UK's perverted definition of that word) human population.
It would be very nice indeed to have new routes every week, and we should be grateful when we do get them, but we really should stop whingeing when we don't. Compare NCL's international services to those at Brest or Rostock. We are very lucky indeed.
*edited to add that we have virtually no inbound tourism either, despite the Newcastlegateshead Initiative's self-justifying claims to the contrary*