Dutch has over twenty million native speakers, Swedish has ten million. That is not ridiculously small. Even Norwegian's four and a half million is, on a global scale, very respectable. To say nothing of the fact that the number of "translated sources" is not a function of the number of speakers, but of the wealth of the country and the spread of written culture (which is very high in all of these cases).
Moreover the wealth and cultural influence of these countries is a function of their willingness to interact beyond their linguistic sphere of influence.
I was referring to the economics of going after a much smaller market.
A publisher is more likely to target french and german before going after norwegian, thus a non mainstream author may appear in a finnish translation much after the publication in english, if ever. Or a movie distribution company may have less incentive to target the niche of TROMA aficionados in dutch than it does for the spanish ones.
They both would have relatively similar costs for the translation, but a much lower possible return.
I'd say it's a generic trait of niche populations, that they gain better knowledge of languages in which information sources are available.
For example, I've consistently noticed programmers speak a better english than architects, and people who use some $RANDOM_NICHE_PLATFORM speak a better english than people who use $REALLY_POPULAR_PLATFORM, due to being forced to use english references.