Perhaps because the terms Apple wants aren't in line with what Samsung should be accepting?
Why should Samsung settle for anything less than the value they believe their IP, etc is worth any more/less than Apple should?
This article says Samsung doesn't want to settle. It says nothing about Apple wanting to settle. It's possible that Apple has the same exact attitude.
I don't think it has to be all of what Apple wants or all of what Samsung wants. It has been stated before that Apple has at least reached out to stop this.
It is very possible that Apple has the same attitude, we don't know. Like every other story out there, there is three sides to it!