The people leaving Illinois and New York are the productive.The welfare addicts aren’t going anywhere.
The Welfarians will follow taxpayers if the freebies shrink or the ‘hoods become uninhabitable. As I understand it, Minneapolis ended up with a lot of the Welfarian population of the upper Midwest as surrounding states tightened their public assistance policies.
If enough federal dollars are involved, some areas are quite content to attract unproductive parasites; see the fight by some states to take in Muslim “refugees”. The politicians that do this never think they will be the ones carjacked, raped, robbed, or blown up by airliners in office buildings - and they don’t care that this might happen to the people who voted them into office.