A tesla is still around 800k NOK which is a little less than twice the average annual gross salary or a quarter house (unless you live around Oslo or Stavanger).
I'm driving a toyota avensis myself, the test drive of a model s didn't give a good impression. I'm also not prepared to buy a car that expensive, even with taxes my toyota was 350k NOK. Hopefully there will be long range electric cars from some other manufacturer soon. I do have some hope for the solid battery tech that toyota is developing now.
And specifically in regards to Norway, the country exports its oil to other countries and owns its wealth to oil, being one of the largest exporters. So while headlines on electric car adoption are nice, they really miss the big picture.
More sustainable than replacing them with more gas cars?