I find zoo attendance numbers fascinating because in the nation's 3 largest cities (New York, Los Angeles, Chicago) the zoos of Bronx, L.A. and Brookfield all have numbers lower than anticipated. There is simply a tremendous number of competing attractions in those areas while in cities like Omaha, Toledo and Columbia the zoos are the #1 game in town.
This is an old post, and you or others may have seen this insight elsewhere by now -- but if you ask most people in Chicago about a zoo, they think about Lincoln Park. It is in the heart of the city near other cultural attractions like the museum campus, it doubles for many as a park in a generalized sense for people who are not as interested in the animals, and the fact it is completely free attracts parents with children in general, but also especially disadvantaged families and school trips, and less surprisingly, families who otherwise might not be interested in a zoo at all but enjoy any attraction that is free. Locals do take pride in it and while it is not as beloved as the major museums or the aquarium it is still well up there.
Brookfield isn't really viewed by most locals as part of Chicago and would probably struggle to make a tourtists' list of attractions. It is suburban, and to its detriment, this suburban setting can also come off as both literally and figuratively less accessible in comparison. While Lincoln Park often attracts people who are disadvantaged due to its accessibility, Brookfield has sometimes been seen as a zoo for the affluent (this is not a common perspective at all, to clarify, but it does exist) and it is also often seen as out of the way. A few friends of mine have found it difficult to locate compared to downtown cultural destinations, even after multiple trips, including from a friend who travels to a nearby attraction quite frequently. (It helped as a child that my father had once lived in Brookfield.)
Furthermore, it is more expensive for families, and there is no obvious to the typical visitor
incentive to pay more or spend more time there when the ABC species are pretty similar to Lincoln Park, and the Shedd Aquarium has dolphins and cetaceans. I would think orangutan could have helped but their exhibit is so easy to miss that I would feel bad if it swayed any visitor, and the difference in tigers is only a year or so out. The elephants did help in the five or so years only Brookfield held them, they did get some positive local publicity for that. For the most part though, while us zoochatters love that Brookfield has a lot of unique species like pangolin, okapi, wombat, and so forth but there are none further that actually matter more to the average visitor I think than a Lincoln Park equivalent.
This all contributes to why Lincoln Park has become such a fantastic zoo and replaced almost all of its outdated exhibits in such a short time -- when courting donors, they can discuss their inherent accessibility and their ability to educate disadvantaged communities, bringing animals to people who may never see them. The donation is not only public but very visible, and can be easily contextualized as benefiting people as much as animals. They can talk about their role in the community as a cultural institution, as Chicago's zoo.
Brookfield's fundraising has no such narratives, instead often focusing on its role as a conservation leadership center, which is not a strong pitch for people who are not already presumably supporting zoos, or falls to being about trying to keep the lights on.
I do think Brookfield and LA are overshadowed not only by other local attractions but also in both cases by being relatively close to other zoos.