Calling Wichita a "big city" is very generous, but interesting nonetheless.
Wichita has a population of 400K and is in the top 50 in population in the US, I would call it a big city.
There are a lot of "Middle American" cities that don't have what people from the coasts think of as big city vibes but are way more populous and more economically significant than most of us tend to assume. Kansas City, Omaha, and various Midwestern state capitals like Indianapolis and Columbus come to mind as other examples of this.
