I don’t think Chicago or C90 are that bad. I think the biggest reason there aren’t big corridors through the bravo is that they use the downwind legs at 6-12k.
Now what really grinds my gears is coming into the area VFR below the Bravo and being nose to nose with an airliner. My most famous example is departing KDPA northbound and playing chicken with a JAL 777-300.
Tower: N1234, you still up?
Me: yup
Tower: N1234, you see that 777 heavy at your 12 o’clock?
Me: yup…
I still think Chicago approach could figure it out, they just want the entire airspace to themselves, I’ve never been cleared through the ORD Bravo except once when I was going to land there, which turned into an event (approach vs tower arguing) and later it was stay clear of the Bravo after I’m already in (this was at midnight). Bravo starts at 3000’ at the lakeshore. If I want to be 2800’ that’s my right, I rather get rolled over at 2800’ vs 1800’. There’s no time to fix any emergencies at 1800’. I was VFR FF and ORD was attempting to vector me in inconvenient ways, I’m tired long day just out of bad weather earlier and the last leg they are playing games. Most ORD traffic is 737s, I fly by those all the time without incident. I’d probably be more concerned with 747 cargo. So I give ORD a fail…