Is it possible that incarceration had the intended effect? Did an entire generation grow up seeing their fathers and uncles locked up and decide that there must be a better way?
Absolutely not at all. I have a lot of experience with the justice system and I can tell you that incarceration has almost no positive benefits for those that are redeemable.
And for those who cannot function in the real world (i.e. serious untreatable mental problems resulting in constant criminality) we need to find a softer way to keep them separated from being able to harm the public.
I would argue that not having a male role model in your life is way worse than seeing the consequences enacted on another.
This even if their was a gain from watching others suffer, the lack of discipline, guidance, sternness, is way more detrimental than the positives of fearing the consequences