I live in the area. They completely redid I-94, which was probably necessary anyway. What wasn't necessary was the complete rebuild of all the frontage roads and county highways in the area. I feel for the people that lost their house under imminent domain.
There are still some people here who think that either Foxconn is still ramping up, or that it's the current administration's fault, or that they're actually still hiring a bunch of people. I personally don't know a single person that's worked for Foxconn in the area, but I do know a few people in construction that either worked on the plant or on the infrastructure surrounding it.
The deal did have a stipulation with tax credits that Foxconn had to meet certain job numbers by specific dates or it had to pay them back. To my knowledge they have been paid. But yeah, as you pointed out that doesn't factor in the massive change to infrastructure.