How do you know the Nordic model won't work if you don't try it? Do you have data to indicate that Nordic model prisons don't work if there's violence? Citation needed or it's not a helpful anecdote. Did you know they're trying it in North Dakota? [1] By making this kind of unsubstantiated claim in support of the system as-is without making any suggestions of your own you're implicitly advocating for the status quo.
And of course some people have severe criminality issues but IMO those should be treated. Even treated as mental health issues.
Aren't you ignoring low crime countries with brutal criminal justice systems such as Thailand? It is far more likely the culture of a country that predisposes it to higher or lower crime rates (and the types of crimes). For example, the deeper the black community becomes entrenched in the hip hop culture, the more crime they commit. You see a black person from any financial class adopt white culture, you will find that they succeed. The more they adopt hip hop culture, the more they are failures, criminals ETC.
And of course some people have severe criminality issues but IMO those should be treated. Even treated as mental health issues.
[1] https://www.motherjones.com/crime-justice/2017/07/north-dako...