Well it's a bit of a phenomenon in the middle and east side of the U.S that's been going on over the past 15 years or so, a lot of the shopping malls that were once thriving in the past are now abandoned or close to being closed down. There's a really good youtube series about it called "The Dead Mall series" by Dan Bell. https://www.youtube.com/playlist?list=PLNz4Un92pGNxQ9vNgmnCx7dwchPJGJ3IQ That was the main source of inspiration for the theme.
As far as the time for the idea, we came up with it exclusively for the jam, after we heard about it so about 2 weeks.