the situation is really bad for politicians. A politican voting to reform a clearly broken prison system faces tons of risks to their career.
Even one wrong vote for improving the prison system will get you labeled as "soft on crime," a dangerous liability for Democrats and nearly a death sentence for Republicans.
Every change you make will inevitably produce a litany of stories about criminal X who was given "too little" punishment. The media will pick these highly emotional narratives up and the blame will be laid at your feet.
You can gain great political capital by making prisions more harsh (who doesn't like seeing a guilty man get punished?) but expose yourself to a ton of downside risk for trying to go the other way.
Nothing about this situation changes until societal perspectives change or politicians don't have to face downside risk for trying reform.