What clout? Chicago is a corrupt cess pool. You don't think that if Southern IL became a state they would instantly enact pro-growth policies to sustain themselves?
New economic activity is almost always generated by cities and later it is spun off to lower cost areas where the creativity is not needed and production proceeds as a rote procedure.
Southern Illinois does not have a sufficiently expanded Division of Labor necessary for new industry to establish itself.
As an example, in my little south Arkansas town were I was born and raised there were very few who could play bridge - in Chicago there are hundreds of clubs. My job would have never existed in Crossett. In Chicago I could work as a Financial Analyst. My biggest wish would be to hired as a production worker at the local paper mills, the best paying jobs in town.
Ever wonder why people continue leave such areas and migrate to the cities? And we will not even get into the cultural experiences available unknown in less urban areas.
Don’t let your hatred of their political machines distort your view of the economic value of cities. I share that hatred but the truth is the truth