A collective punishment was fit for the many family members the prince had wronged and/or executed for no cause. And you are correct. Some will never change. It's akin to our modern day justice system however broken that realizes some individuals will never repent.
I'm so pleased you found the series interesting. I appreciate your kind compliment and support throughout the saga. I wish I had the time to incorporate the indepth world building and personality assessments for all the characters.
Take care and have a good rest of your week.