And I'll let you know that my shortest days are 4.5 hours long (with weak sunlight!). Oslo has slighly longer days still.
This is not just question of "more expensive country, more expensive stuff". Switzerland or Luxembourg are quite expensive, but you will buy affordable and good Italian/Spanish/French wine there, because these countries don't impose anywhere near as much taxation on wine.
It's actually relatively cheap right now, I expect a price hike soon given how much grocery prices have increased.
EDIT: Ahh! I was basing my statement on data from quite a number of years back, and just assuming prices tend to go in one direction in inflationary economies. The nuance here is that the NOK has weakened somewhat dramatically against the dollar, so relative prices aren't quite as insane now as they were in the past.
For booze above 22% ABV the tax is currently 9.23 NOK. So a 0.7 liter bottle of 40% ABV Whiskey or similar would get 258 NOK or $27 / €23 in tax.
And on top of that comes the usual 25% VAT, and high wages to our bartenders etc.