When I was in the Chicago area, I paid no tolls when I entered and exited the tollway within the same region. Perhaps that has changed within the last 10ish years?
It doesn't seem practical to charge tolls at every onramp.
It is zone-based. If you are close enough to a plaza, you won't be tolled getting on, if you're just after a plaza, you won't be tolled getting off. The toll for each ramp is more expensive the further it is from a plaza. It's possible for you to hit only one ramp toll in a short run, but if you were to math the total paid on any given route it will work out to be roughly linear with your distance.
It was very much on and off for many years. It was intended to cover the costs then go away. Instead they installed stream lined overhead tolls to not have to wait at the toll booth anymore and now it's just a perpetual tax.
It's also partially owned by outside investment (specifically the skyway from Indiana)
Very interesting. That still doesn't imply the "poor bear the brunt" (the original GP's assertion). Likely the inverse - since again, businesses and wealthy individuals are going to travel by vehicle vastly more than "poor" individuals.
Ha ha, definitely changed in the last year or two. I've been to Chicago a few times only to get a nice bill in the mail for tolls (I live two states away). When it's all done electronically, you sometimes have no idea you've had your pocket picked. ;-)
It doesn't seem practical to charge tolls at every onramp.