I wonder if it might have been water. They may have needed more than a sweetheart deal with the state. I think a big reason for the location was the water supply via Lake Michigan. They got a waiver of state environmental laws as part of the deal, but they still had to contend with federal laws, and a treaty with Canada that governs water use in the Great Lakes watershed.

There was quite a controversy over the environmental impact of this plant. The "word on the street" is that LCD manufacturing is a dirty industry requiring a lot of water.