Why is it hard for European translation agencies to cost less or have fixed rates?
Because European translators live in Europe and have to make a reasonable living themselves; fixed rates are a much more significant issue because of European languages, rated in varying ways. For example, German is the most expensive European language for translation and is somewhat infamous for that phenomenon. All Eastern words cost much less, but the translators are hard to find.
The economic prosperity of the target region, the prevalence of translators in their culture, all play a significant role in price. Spanish, Italian, and other mainstream European languages will not need to look around too much to find a translator. They are, as such, more affordable than German.
Question remains, is anyone able to do Norwegian to Swedish translation without using English?