The problem the Bears have is they've already horsefeathers the bed with Pritzker and a good chunk of the General Assembly for the reasons @mul21 mentioned. The grumbling come out of this last session was less "screw the Bears!" and more "how does a Bears deal benefit Peoria, or Rockford, or Carbondale?" The Chicago contingent of the general assembly was fully on board for *something* (especially since they were under the impression the Bears could stay in Chicago), but the PILOT bill was only going to benefit mega-projects in and around Chicago, the Bears relied on lobbyists in Springfield without actually going down to stump and court votes, and no one had a backup bill ready if the PILOT bill failed.
I'm unsure how this ultimately plays out, though, because the Bears have Indiana over a barrel at the moment. Firing Warren would show they mean business about Illinois, yes, but if Illinois' best bill falls short of what Indiana is offering, would the Bears stay regardless? I'm unsure about that.