The main difference I see between Illinois and CA/NY is that the cost of housing is MUCH more reasonable so that the overall cost of living in the area is MUCH more reasonable.
It's not more reasonable when you consider the property taxes. A $350,000 house looks great until you factor in $10,000 annual property taxes.
Even when taking property taxes into account it is. look up how much comparable homes to that 350k home in illinois are in NY/CA and how much their property taxes are in addition to that significantly higher home prices.
And you have significantly fewer opportunities to earn income.
3% FMV property tax is pretty rough, but do you get a tolerable school system as part of that bargain?