It is well known that Norwegian earned their money on Norwegian domestic flights and on flights from Scandinavia to southern Europe.
Overall the longhaul branch was operating with massive losses, for the following reasons The management had no idea how intercontinental flights operate, it is a completely different ballgame than short- medium haul operations.
The mistakes they made regarding longhaul ops, were to utilize a new completely unproven and very expensive. aircraft
with no business class.
Their cargo. operation was a complete disaster.
As all the money they were earning on the good short- medium haul routes were used cover the losses from longhaul , forcing the company to continue a completely unsustainable expansion, just to generate some cashflow, among other things leading to the catastrophic Argentinian adventure.
Some will say that a few of the longhaul routes from LGW were making money, and that may be true, but not nearly enough to cover the massive losses from the rest of the longhaul ops.
The only one who has ever had any success with low cost longhaul was Sir Freddy Laker with his Skytrain, until the operation was killed by BA and other airlines.
There are a few other lowcost longhaul airlines that were operating pre corona, They were also not doing that great, but most of them has business class, and they are either owned by legacy carriers, or other large companies that have other revenue streams.
Norwegians way of low cost longhaul was always doomed.