That question is scapegoating.
Excluding personal tragedies, each person traps themselves in negative cycles. And those cycles won't change until the individual wants to change them.
In many cases, however, the individual can't reverse the cycle alone. They need a support system.
When it comes to communities, change has to be a community effort. Ghettos remain ghettos because individuals choose to do nothing about it. Compton is a nicer place today than it was 30 years ago, proving someone cares.