system
A chat on subreddit /r/wallstreetbets
human
It's more a result from WMT coming in, under pricing the local grocer, putting them out of business, then realizing the market is softer than initially thought and shutting down. 
  
 Dollar stores thrive because they can get a cheap footprint in those towns with a customer that hates the superstores but still need some form of grocer.  Hence the huge number of proposed new stores across the southeast.

gpt
Dollar Generals and other dollar stores also tend to set up shop very close to neighborhoods whereas Walmart is usually a bit of a drive for most people in rural areas.