To all those Illinoisans who opposed the progressive tax back in 2020: you’re being proven more right every day. Illinois would have become even less competitive at a time when more and more states are increasing their economic competitiveness by moving to a flat income tax.This year alone, four states decided to transition their individual state income tax from progressive to flat:Iowa passed a law that will turn its progressive tax into a 3.9% flat tax by 2026.Georgia’s income tax is scheduled to convert to a 5.49% flat rate by 2024. Mississippi will go from a progressive tax to a flat tax next year.Arizona, after a lengthy court battle, has finally won the right to transition to a 2.5 percent flat income tax in 2024.There are also movements in Wisconsin and Oklahoma to make those states’ taxes flat as well.Both Georgia and Arizona’s change to a flat structure are not automatic and must meet certain financial conditions to occur.