Very true, and I do not expect that we would ever approach the levels of instate dominance you see in Wisconsin, let alone Iowa or Nebraska. However...
1. We realistically should have Iowa-level dominance in Central Illinois - a population of over 2 million people. I would say we enjoy this level of support in the areas around Champaign, but it remains a realistic-if-optimistic goal to have kids in Peoria, Springfield, Bloomington, etc. growing up as diehard Illini fans regardless of where their parents went to school - the kind of thing I can say happens in Iowa from firsthand experience.
2. We should shoot for Michigan State-level appeal in Northern Illinois (excluding Chicago) and Southern Illinois, IMO. In other words, it might take a parent being an alum and/or having a connection to the U of I to be a big fan, but we should also pick up just as many if not more casual fans as out-of-state schools. For example, a high school kid in Rockford looking for a team to cheer for should not be MORE likely to cheer for the Badgers than the Illini ... same for the Quad Cities and Iowa/Illini, the Metro East and Mizzou/Illini, Southern Illinois and Kentucky/Illini, etc. I think we are punching below our weight here.
3. It is probably only realistic to expect our Chicago Area fan base to mostly consist of alumni and their families (though I myself am a contradiction to this being a non-alum fan in Chicago, and I will say there are more of us than is assumed!!). However, just given the massive population of the Chicago MSA, we should always be doing aggressive fan outreach up here. Even just picking up a small percentage of the unaffiliated fans who think to themselves, "Hey, I guess the natural choice is to cheer for the state school" equates to a significant boost in fan support. * Additional comment at the bottom, slightly OT.
This all obviously must compliment engaging Illinois' massive alumni base. I feel right now that we are about equally average (given the expectations for each category) at engaging our alumni base and #1-3 above. Just by engaging alumni and doing #1 effectively, you already would have a bigger football fan base than Iowa. If you do #1 and #2 well, you are talking a program whose TV following likely keeps it safe in any conference reshuffling in 10 years or so. Obviously, if we ever did all of these even at a B- level or above, you are talking about a VERY large fan base.
Obviously that was a bit of a ramble, and people might not agree with my assumptions here. My personal guess is that by being about a B at engaging alumni, a B+ at #1, a C at #2 and a C- at #3, we end up with a football fan base that would have a "gross" total of fans somewhere between Iowa and Wisconsin, but our "active" fan base would be between a Maryland and an Iowa. Again, just total guesses.
Either way, I think all can agree there is room for improvement regardless of how high or low the ceiling is, and it will be essential to engage as many potential fans as possible in the next decade as conferences realign. At least IMO. While we might think our situation is difficult in some ways, we should be thankful we at least have this room to improve. There are only so many alumni a school like Northwestern or Wake Forest can engage, and there are only so many potential fan populations schools like Kansas State, Iowa State, Ole Miss, etc. can even tap into in the first place. Again, sorry for the rant, haha ... fan base size/geography/dynamics/etc. is one of my more obscure side obsessions.
* I will also die on this hill RE: Chicago NCAA football fandom after living here since 2019 and somewhat aggressively trying to notice the college sports apparel we see around in that timeframe. Chicago is obviously a pro sports city first and foremost, and that must be taken into account. It is also a cosmopolitan city that has a "trans-state" feel that only so many other cities like New York have (compared to an undoubtedly major city like Detroit that is nonetheless quintessentially "Michigan"), and this means TONS of alumni from other schools that will always keep Illinois from dominating the market. You also have a strange obsession with Notre Dame from a vocal (smaller-than-assumed-by-most) minority that supports Notre Dame because of the Catholic angle, and that will always be a factor. With that said ... I have lived here while Northwestern made the Big Ten Championship Game, Iowa football was ranked #2 in the nation, Michigan literally won a National Championship, Notre Dame made the College Football Playoff, etc., and I will say this - NO school actually increases its ceiling for fans here when they are good like Illinois. I always see a good number of Notre Dame and Michigan shirts, but it barely increased when they each had generationally special seasons. Meanwhile, Illinois will go from a "first among equals" status among the crowd to decidedly #1 in relatively short order when we get good. The uptick in 2022 was very noticeable to me, and the basketball uptick since I moved here (again, we were bad then!!) has been VERY significant to the point that I am convinced the #2 basketball fan base is a materially distant second. It is my pretty strong opinion that regardless of where things stand today, the "casual" or "unaffiliated" or whatever college sports fan in Chicago is decidedly more likely to jump on an Illini bandwagon than any other school. Unfortunately, it ALWAYS takes wins to attract a casual fan.