Kansas has 2.9 million people, Oregon has 4 million people. Kansas 2016 GDP growth was 0.1%, Oregon's was 2.7%, above average. A Kansas judge ordered the state to spend more on its schools, admittedly Oregon schools are underfunded because of Measure 15, but no judge has ordered the state to spend more. Illinois lost more people in 2015 than any other state, a staggering 22, 194 people; but Illinois has a population of 13 million. Gosh, it's like the refugees leaving Syria! From 2015 to 2016, according to Wikipedia, Kansas lost 5000 people, although the census bureau says that from the 2010 census to 2016, Kansas population rose by 1.9% or 55,233 people, for an average of 9,205 people per year. If you look at the growth rate maps, Kansas grew much slower than all its neighbor states.

Illinois has a big problem with its retirement system, but it's a big state with a big economy. None of these stats have anything to do with lack of funds for schools. Huge tax cuts do.