It's just a very very large city that attracts graduates from schools all over the country you're just not going to get a predominant group in a city that big.Broadly, Illini just can't get a lot of Chicago metro traction, it seems to me. Particularly true for football but somewhat true for early & regular season basketball too. Just unable to get the city really engaged in our Illini. There's barely an Illini bar presence. Someone mentioned the Budweiser Brickhouse being Champaign north but my experience (limited) with that has been very disappointing.
You don't have season ticket holders for this game and there really aren't that many tickets available though and the majority are in the far upper deck. It's only Monday afternoon and I'd bet a lot of tickets tend to get sold a day or two in advance especially since those tickets tend to drop in price closer to tip off.
Sidenote: the 8 pm tip on a weeknight isn't a great time for bringing in the fans from the suburbs. 7 or 7:30 are just better tip times for central time.