I think you hit the nail on the head. Chicago closed the Cabrini Green housing project. Where did all of those people go? Dupage, Will ctys?
They were told where their Section 8 Vouchers were valid. If they accepted the vouchers, they didn't have freedom of choice in their destination.
Some were directed South to places like Chicago Heights and Ford Heights and others went North toward Zion. Some even went across the border into Wisconsin.
All coordinated by the Democrat Party Machine.