It's a complex question, so forgive me if I'm a bit wordy on this one (and lots of guesses, so I could be entirely wrong). Mostly it's a historical issue, but also partly the range of industries that are/were in town. I'm thinking Carle, Kraft, Busey, and the other larger employers (which is kind of a reflection of the historical issue).
For the historical piece - the University is one of the earliest land grant Universities. Like the other land grants (I think) it was originally an Ag school so all the most prosperous farming families sent their kids to town for a time for multiple generations. The town also got more important as a waypoint on the City of New Orleans, and the intersection between I57 and I74. So, over 180+ years there's been a concentration of wealth in town - has to be the largest in the state outside of Chicago. That wealth, proximity to chicago and cross-continental transportation routes, and a cheap student work force brings industry to town which for the most part has stuck around throughout the years.
All of that raises the demographic economic base of the town, but the University is the biggest driver there by far. No other employer can hold a candle to their benefits. Salaries are crazy high too - take a scroll through the grey book sometime and look at the high-five through mid-six figure salaries (if they're faculty that's a 9 month salary - they get more for summers, research, publications, fellowships, and more). There are some ri-hi-hich folks in town and that's just the University. All the attendant industry also makes bucks. The University also provides some free-money incentives for housing - outright purchases or stipends. Students coming to town are also generally pretty rich - we have (had) the top three Chinese student population in the country. Undergrad population is 37K or so and out of state tuition is $30K or so, so those are some decent numbers in terms of welcoming rich folks to town, along with all the additional money injected into the community by rich kids. It's a public Ivy school with one of the best Engineering schools in the country - so it's a strong international draw.
That much money has historically increased property costs. We'll see if that trend reverses with Covid and the rampant overbuilding in town, but I think minor corrections in town it's still a secure market. Now, if you'll excuse me I need to go run the numbers on a run-down duplex I just looked at that I almost certainly will never buy. Ah, practice!