Black history is filled with examples of what you're talking about. Every single time we create a self sustaining community they destroy it. Whether its Seneca village or rosewood, they always come in with the power of institutional racism to destroy what we build.
Some peoples spirits have just been broken and there is no desire to try anymore. People who think that what they have will just be taken away don't try to obtain anything they cant expend quickly.
The black lower class like the white lower class will benefit from medical care, supplementary education and after-school programs, and things like job training programs, paid time off and fair wages.
Give people easy access to medicine and they will be less likely to self medicate with drugs and alcohol. Give job entry programs to former felons and they're less likely to enter back into the system. Give kids guest speakers and black teachers who can break the knowledge down in a way that seems relevant and you'll have less kids skipping school. Make college more affordable and you'll have less kids saying 'im not smart enough to get in, and even if i did, I can't afford it'. Give parents daycare programs and they're less likely to neglect their kids. This kind of stuff has a precedent for working. Neighborhoods were more peaceful when the black panthers ran things because they produced security, they fed people, they educated people and they gave parents relief. Naturally the white establishment had to attack them.