It's not undeveloped, there's a park and music venue there now. I don't think it is a leap to say it is now used by many more Chicagoans than the airport for private jets ever was, even if most Chicagoans are unaware.
Today instead of X's the bulldozers could have engraved an acronym, and he could have argued it was for an immediate good cause. Aka acronym-washing.
BTW, I would suggest "levelers" as another label to consider, but then Wikipedia would need some disambiguation: