The main species of Coffee are:
Coffea Arabica and Coffea Robusta.
The Robusta is inexpensive, slow growing, and not very flavorful. It is also processed into Instant or Canned Coffee. Often “Commercial-grade” roasters will use this type of Coffee to blend, to reduce costs and make more profit.
Some of those all night dinners serve their house blends and this is the cheaper coffee.
Reference: “Coffee Cafe” by Sherri Johns