My kids go to a school in Spain and they get a 3 course meal every day for about 5 EUR a day. As a parent its great because you know they've had a full complete meal every day and you can just make a small evening meal.
For starters, Norwegians do not employ rye bread.
Furthermore, Norwegian open-faced sandwiches have not evolved into full-blown smørrebrød - where stacking multiple ingredients is such essential part, that you cannot eat the common smørrebrød without cutlery.
Case in point: https://www.valdemarsro.dk/luksus-stjerneskud/
At my university, we would lunch in groups, building such works of art during lunch-time from shared packs of ingredients.
It may be that Danish school children get a "boring" lunch, similar to the Norwegian one. However, as Danes grow up, their lunches evolve in tastes and complexity. It seems less so in Norway, and that's OK, but a tiny bit boring :-P