I'm in Norway, and tradition until relatively recently has been to bring a few slices of bread with ham, cheese, pate or whatever wrapped in paper. Sometimes left overs from dinner the day before. Almost always consumed in a canteen with your co-workers. More recently many work places have a canteen with both hot and cold food for a discounted price. If you don't have access to a canteen the shops sell relatively cheap sandwiches or micro wave lunches.

Yeah, it’s pretty boring.

Interesting tangent: Lobsters were once so ubiquitous (both in Europe and the US) that they were considered a food of the poor. There are even records of servants petitioning their masters to not be fed lobster more than 3 times per week.

Supply and demand, I suppose.

These days lobster is a bit of a luxury item even in Maine.

Not really, in the end it comes down to the person who decides what price to put on the sammich.

Yes, because it is a luxury good, an expensive sandwich can even be in more demand than a cheaper one, even if all other things stay the same such as its composition.

"Hip" sandwiches and salads are a thing.