You're forgetting English. Learning a foreign language is really hard and many people learn English as school/by listening to music/by watching movies/TV series/etc. Few people want to go through the hassle of learning another foreign language.
Yes that is a key issue, but most people don't even get to the point of investigating the language situation. You don't have to learn Norwegian to live and work in Norway. I have friends who have lived here for over 10 years who can barely say a word of Norwegian.
