the difficulty here is other than relatively minor drugs dealing/possession and the handful of political prisoners from Palestine Action / environment protests, this is already happening in recent years (*apart* from a populist trend to put people inside for those minor drugs offences)
Most people who go to prison in my area have used violence and hurt someone. In many cases, more than once.
I think (as well as rehabilitation), a *lot* more effort should be put in to violence reduction and de-escalation when young men interact, this could keep them out of prison in the first place..