I'm getting strong "California uber alles" [1] vibes, even though it's Chicago.

It's the suburbs of Chicago. Funding for schools is largely from local property taxes, which creates large gradients in the quality of those schools between towns.

Towns with better school districts command higher property values, creating a positive feedback loop in resources but also pricing younger families out of those same areas.

Another typical situation is a divorce, where one parent moves out of the expensive town but still wants the kids to attend the same schools for continuity.