My bet is they will wait till the recession and go for the assets in the subsequent resulting firesale
If you are interested in the issues surrounding Norwegian and want to pass comment on them why not inform yourself on the subject first? Willie Walsh, CEO of IAG, has made two offers for Norwegian in 2018 and is on the record from a couple of weeks ago saying he is still interested in buying Norwegian right away if the price can be agreed. The price he offered by the way is over twice the current market Cap of Norwegian.
As anyone can imagine opening new routes is an expensive business because even good routes are very rearly profitable from day 1, it takes time for a new route to become stablished (a minimum of a year?). Growing an airline is also expensive because it implies a whole raft of one off costs, like training new crew for example. In addition the issues with the RR 787 engines have brought costs that should not be ongoing. All those one off costs are the reason why Norwegian is no profitable, or bearly so, right now. In the other hand once you have made those investments running costs should be much lower and as new routes become consolidated the airline should be quite profitable. For these reasons judging Norwegain´s business model with a static picture of 2018 misses the point.