Probably because in Norway, the state-owned liquor stores have people on the payroll much better paid than in other retail stores there, and so costs of operation are higher, making liquor prices higher?
I think they purposefully keep prices high to disuade drinking. Mind you this was about ten or fifteen years ago so things may have changed.
Just another example of the fine style of government in the socialist countries of Europe. And the HildaBeast (and her ilk) want to put it on you.
Its the tax on liquor that makes it mor expensive