Double stairways and building code requirements don't seem terribly onerous to me. However, the parking minimums and traffic flow requirements do. In Dallas, each 500 square feet of a unit is required to have a parking space... A parking space takes up 300 square feet on average. This means your apartments are at LEAST 3/5 parking.
This means you get complexes like this one where it's more parking lot than housing and that land is VERY expensive.
The double stair means there is no practical way to make a four bedroom. try doing a layout and you discover you have a lot of space that isn't useful. (bedrooms require a window)
This means you get complexes like this one where it's more parking lot than housing and that land is VERY expensive.
https://www.google.com/maps/place/Bridgeport+Apartments/@32....