You cannot just take a system that works some place in the world and transplant it to another, completely devoid of any cultural context associated with it. What works for Norway would probably work really well if applied to most middle-class Americans. I seriously doubt we would see much success with a system like that applied across the board - there are too many other problems keeping our recidivism rate up, such as lack of support after jail, the lucrative nature of the drug trade, the way we structure our prisons to support gang mentalities, the lack of opportunities for convicted felons, etc etc.
Since we're being honest here, if someone murdered someone close to me and then got unsupervised weekend parole after 7 years, they'd be dead in an alley their first weekend out. Maybe Norweigans are very different, culturally. Maybe I'm just a vengeful asshole who should just deal with it - but I doubt I'm alone over here. But this could also just be a reaction to violent crime - I don't feel as though most non-violent crime deserves harsh sentences. Hell, I'd settle for large fines in most cases.