I think the reason is that expanding into a new country might be too big a risk due to the product and regional taste preferences. Or perhaps the situation is too comparable to starting a new chain from scratch.
I’m no expert on Norway or Denmark, but I could imagine that F&B wouldn’t necessarily work there. Germany/Austria, on the other hand, might be somewhat more similar to Switzerland, but there could still be differences.
We went to Switzerland for our summer vacation, and my only “must-see” attraction was Holy Cow 
The burgers were alright, but for a Finnish palate, F&B beats them hands down – we had just visited Friends a week or two earlier, so it was a good benchmark. The price level in Switzerland did make me laugh; I recall a meal costing around €28, though at least it included a beer. You can get a meal at Friends for about €15–17.