Okay, sorry to jump on you for my assumption that you were saying "my city is better than yours." You're right, but Chicago is not some city that's dying like Decatur, IL, or Pine Bluff, AR. To me it's just insane that People are so misinformed on how great a city it is. Apologies.
It's still growing though and Downtown vibrant. No one here likes Lightfoot. She's awful and will lose the next election.
Only 11 of the top 50 cities in the US have a Republican mayors, and they're not really the place anyone would describe as interesting places to live. Jacksonville (rated one of the most boring cities in the US), Fresno (one of my hedge fun managers I worked with was born and raised there. She calls it the "Armpit of America"), Fort Worth (one decent city), Oklahoma City (Yawn), Mesa (shrug), Omaha, Colorado Springs (Religious right loons), Miami (Great City), Tulsa, and Bakersfield. Wow. So out of all the cities run by Republicans, there is one "cool" one.
"Why is such a great city the slowest growing large city in America?": Property Taxes that are TOTALLY out of control, cold winters, and a high crime rate. Cities all across the rust belt are seeing the same problems.