Completely disagree with this take.
If you have 8-10 vendors on-site, they are "fighting" for customers. I'd also wager that majority of crowd doesn't eat in the stadium; most get snack food such as peanuts or popcorn.
Also, restaurants best profit comes from bar sales, which isn't an option at Cajun Field.
I think it works well for Dean-o's b/c there isn't much competition currently and it's an easy meal to prep & serve. Not sure this model would work well for alot of vendors.