I don't think it's possible to abolish prisons for all crimes. But why does a thief or a drug dealer (or worse, just a drug user) need to be in prison? What about the nature of their crimes necessitates imprisonment as a reasonable method of corrections?
If the point is stopping people from reoffending, prisons don't do that. Like objectively. Recidivism in the US is super high, and going to prison predicts increases in the severity of crimes people commit.
So, what reduces recidivism? Eliminating the factors that drove them to crime in the first place. So, you monitor them closely - house arrest, assigned social/case workers, etc. Like a more robust parole system for nonviolent offenders. With enough surveillance, you can reduce the likelihood of reoffence by making the chances of getting caught much higher. This enhanced monitoring would be temporary.
For violent offenders and more serious criminals, maybe prisons are still necessary. But they don't have to be dehumanizing and can provide necessary health/psychiatric, educational, social, and job skills training.
You could make the corrections system more effective by making society easier for criminals to reintegrate into. If you're a felon and you can't find work because you're a felon - how are you going to afford to live within the confines of the law? Step 1) jobs programs for felons with a path to eliminating non-violent offenses from your record as it relates to work with exceptions as necessary. Step 2) improve the education system to prevent people from turning to crime and to help give former criminals relevant job skills to earn an honest living. Step 3) provide healthcare to people - having access to healthcare for mental and addiction-related conditions is super important to reduce crime.
Basically - prison abolition isn't about just letting rapists and murderers go free with no consequences. Instead, people in favor of prison abolition are typically in favor of reducing the societal pressures to commit crimes and preventing reoffense.
In part, sure. But it's also a failure of the voting public - primarily by not showing up to vote. The historic trend of low voter turnout got us to where we are today since it has enabled a minoritarian party with interests contrary to the vast majority of their constituents to win elections and shape the political landscape in ways that favor them.
It's also a systemic failure since the US makes voting about as difficult as they can - but, again, that is mainly the fault of Republicans who have crusaded for years to repress the votes of minorities, women, and basically anyone who isn't old and white.
It's easy to blame the dems because they should have defended better, backed more pro-worker policies, etc. But if all eligible voters voted, basically no Republicans would ever win elections in this country. Maybe then we could have some actual progress attacking dems from the left.