Cole, it took some searching and a lot of reading the same things over-and-over, but I found a site that straight out says there is Fusarium Wilt in Illinois.
https://ipm.illinois.edu/diseases/rpds/929.pdf Only citing this part says a lot. This was from 1990 - 27 years ago.
"Illinois now has over 4,000 acres of Fusarium-wilt infested
soil. If suitable resistant or immune varieties were
not widely available, wilt would undoubtedly be the most
damaging disease of tomatoes in this state."
I never doubted what you already knew. I knew there was something else wrong with my gardens too. In my case, RKN takes longer than Fusarium wilt does to mess up a plant. Fusarium wilt is why we are getting tell-tale signs so early in the season.