Not the OP but as someone who grew up in Chicago, but then spent a large time in NYC, here are some examples:
1. Talent Density: Chicago is optimized talent-wise at a regional level (the midwest), while NYC is optimized at a global level. Chicago simply doesn't have the same pull if you don't live in the midwest the way NYC does for folks living anywhere across the world. This creates an obvious talent gap.
2. Culture: Chicago operates as a much more of an all-American city, reflecting cultural attitudes not too dissimilar from the rest of the country. Examples here include a heavy sports culture, emphasis on drinking/going out. You see a similar trend with NYC transplants (like myself in my early 20's) but you're eventually forced to grow out of it in NYC and create a more unique and diversified identity. I haven't seen much of this in my social circle from Chicago who never left.
3. Industry Density: Chicago is considered top at a few select industries including insurance, commodities etc. OTOH, there are very few industries that NYC would not be considered top in. Strong talent begets strong talent and this creates the sort of network effect that's present in the bay (for tech), and in NYC, but not in Chicago minus a few industries. These network efforts, over a long enough timeframe, fundamentally alter the landscape of one's career.
4. Local v.s. global maxima: Chicago allows you to reach a relatively easier maxima (career or culture wise), which likely means Chicagoans are happier on average. That concept doesn't exist in NYC or the bay. It pushes you to reach a global maxima which is inherently more challenging. For example, getting a job at Google likely sets you for life in Chicago. In NYC or the bay, that's simply a starting point. This isn't for the faint of heart but is highly rewarding if you're ambitious and work-oriented.
5. Arts and Fashion: The same concept of local v.s. global maxima exists here too.
6. Food: Far more global and unique in NYC than in Chicago (which in-itself has great food)