A good solution would be to make drug/alcohol rehab available at no cost to all who want it. There are AA and NA meetings in pretty much every city, almost every hour, in So Cal, which is very helpful, but not the same as full blown lockdown rehab, which is criminally expensive. That having been said...people have to want sobriety for it to work, and many will say they do, but really don't, as they can't even get to a free AA/NA meeting.
There is someone who was my best friend in my late teens and 20's. He's a homeless meth addict and alcoholic. Has been for around 35 years now. Horrific dysfunctional relationship with a woman he has three kids with. She OD'd a few years ago.
One of his kids became an alcoholic (of course he did, with all the dysfunction and addiction with his parents). That kid embraced AA, and recognizing that his father was a trigger, told his father he didn't want to be around him unless dad also got sober. Dad chose to continue using.
Another of his kids, because it was also an abusive household, a few years ago he attacked one of his acquaintances with a skateboard to steal a cell phone, left the victim with brain damage. Got out after a few years, and within two months, attacked an elderly parking lot cleanup worker for no reason whatsoever (he had immediately gone back to alcohol and drugs after his release from prison). Left the worker with a coma and brain damage. He was arrested, then murdered his cellie when he found out he was in for failing to register as a sex offender (that was because the jail didn't classify and house inmates properly.....you don't EVER house a sex offender with someone who has done hard time for a violent crime). He's going away for a long time, I think his first parole eligibility date is 2035 (honestly, he should NEVER get out).
Third kid seems to be doing fairly well, but has no relationship with dad.
All dad has to do to re-establish relationships with his kids is to get sober, but he won't do it. I last saw him about two years ago....and I was horrified to see that he had absolutely no teeth left whatsoever (ain't meth great?). I offered to get him into rehab (I know people), sober housing, and even told him I would look up a local AA meeting and I'd go with him right then, even though I've never had an alcohol/substance problem. He actually got angry, and went off on a rant about how his one son abandoned him for his new AA family. BTW....that same son who embraced sobriety was homeless but entered the Cal State University system and just graduated with a degree in psychology. He is now housed and has a good job.
So....a good start would be to get as many people into rehab as possible. Nobody who wants to get sober should be denied the gift of rehab because they can't afford it. By the same token, those who commit crimes need to have some form of a hammer hanging over them, and right now in California, there's not. Before the change in drug laws the threat of jail time was good incentive to steer people into rehab....there were a lot of people I arrested who returned a couple years later specifically to thank me for arresting them (there was almost always a heartful talk about rehab options with me whenever I arrested an addict). With no jail hammer hanging over them, there is no incentive for them to stop using and committing minor crimes to support their drug/alcohol habit.