Hey man no politician in Illinois has ever been bought off. I'm sure this law passed strictly because the representatives in Springfield felt it was the best thing for the state, and definitely not because Walmart made a $25,000 campaign contribution.
In all honesty, the pittance is just a token, an indication that everybody is on the same page. The real compensation is that there are lots of sub rosa benefits to the politician during their time in the statehouse or Congress or what have you, and as soon as he or she has had enough of public service, there's always going to be an extremely well-paid consultancy waiting. You have to look at the overall career path.