> the once unified gangs were displaced throughout the broader Chicagoland area, and were able to grow immensely without the constraint of their former static, well-monitored domiciles.
This is not what happened. Firstly, just to get this out of the way, this period in Chicago was a time of gang fragmentation, not growth or consolidation.
There was a rise in violence associated with it, but that was because people who had been warehoused in the west side high rises moved to the south side, where there were already established gangs and relationships between them. This led to conflict in the same way that the New Orleans floods led to conflict in Houston, because New Orleans people were tough and Houston people were tough, so when New Orleans people were moved to Houston, things happened.
Chicago is dangerous because it is an absurdly segregated city containing massive pockets of poverty with no public services, jobs or grocery stores, complete disinvestment from public schools, and a outsized fine and fee schedule. Upper-middle class whites in Chicago are paranoid about it for good reason, the same reason any wealthy person trying to have some bohemian city experience at the edges of a favela would be afraid.